Micron Document
<!DOCTYPE html>
<html class="client-nojs vector-feature-night-mode-disabled vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-sticky-header-enabled" lang="en" dir="ltr"><head>
<meta charset="UTF-8">
<title>Hypergeometric function</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="canonical" href="https://en.wikipedia.org/wiki/Hypergeometric_function"> <link href="./mw/ext.cite.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/ext.math.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.icons.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.search.codex.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/user.styles.css" rel="stylesheet" type="text/css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" type="text/css" href="./mw/site.styles.css">
<link rel="stylesheet" type="text/css" href="./mw/noscript.css">
<link rel="stylesheet" type="text/css" href="./footer.css">
<link rel="stylesheet" type="text/css" href="./vector-2022.css">
</head>
<body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Hypergeometric_function rootpage-Hypergeometric_function skin-vector-2022 action-view">
<div class="mw-page-container">
<div class="mw-page-container-inner">
<div class="mw-content-container">
<main id="content" class="mw-body">
<header class="mw-body-header vector-page-titlebar">
<h1 id="firstHeading" class="firstHeading mw-first-heading">
<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Hypergeometric function</span></span>
</h1>
</header>
<a id="top"></a>
<div id="bodyContent" class="vector-body ve-init-mw-desktopArticleTarget-targetContainer" aria-labelledby="firstHeading" data-mw-ve-target-container="">
<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr">
<style data-mw-deduplicate="TemplateStyles:r1236090951">
/* start https://en.wikipedia.org/ */


.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}


/* end https://en.wikipedia.org/ */
</style><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="Hypergeometric_distribution" title="Hypergeometric distribution">Hypergeometric distribution</a>.</div>
<div role="note" class="hatnote navigation-not-searchable">The term "hypergeometric function" sometimes refers to the <a href="Generalized_hypergeometric_function" title="Generalized hypergeometric function">generalized hypergeometric function</a>. For other hypergeometric functions see <a href="#See_also">See also</a>.</div>

<p class="mw-empty-elt">
</p><p>In <a href="Mathematics" title="Mathematics">mathematics</a>, the Gaussian or ordinary <b>hypergeometric function</b> <sub>2</sub><i>F</i><sub>1</sub>(<i>a</i>,<i>b</i>;<i>c</i>;<i>z</i>) is a <a href="Special_functions" title="Special functions">special function</a> represented by the <b>hypergeometric series</b>, that includes many other special functions as <a href="Special_case" title="Special case">specific</a> or <a href="Limiting_case_(mathematics)" title="Limiting case (mathematics)">limiting cases</a>. It is a solution of a second-order <a href="Linear_function" title="Linear function">linear</a> <a href="Ordinary_differential_equation" title="Ordinary differential equation">ordinary differential equation</a> (ODE). Every second-order linear ODE with three <a href="Regular_singular_point" title="Regular singular point">regular singular points</a> can be transformed into this equation.
</p><p>For systematic lists of some of the many thousands of published <a href="Identity_(mathematics)" title="Identity (mathematics)">identities</a> involving the hypergeometric function, see the reference works by <a href="#CITEREFErdélyiMagnusOberhettingerTricomi1953">Erdélyi et al. (1953)</a> and <a href="#CITEREFOlde_Daalhuis2010">Olde Daalhuis (2010)</a>. There is no known system for organizing all of the identities; indeed, there is no known algorithm that can generate all identities; a number of different algorithms are known that generate different series of identities. The theory of the algorithmic discovery of identities remains an active research topic.
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>
<p>The term "hypergeometric series" was first used by <a href="John_Wallis" title="John Wallis">John Wallis</a> in his 1655 book <i>Arithmetica Infinitorum</i>.
</p><p>Hypergeometric series were studied by <a href="Leonhard_Euler" title="Leonhard Euler">Leonhard Euler</a>, but the first full systematic treatment was given by <a href="Carl_Friedrich_Gauss" title="Carl Friedrich Gauss">Carl Friedrich Gauss</a>&nbsp;(<a href="#CITEREFGauss1813">1813</a>).
</p><p>Studies in the nineteenth century included those of <a href="Ernst_Kummer" title="Ernst Kummer">Ernst Kummer</a>&nbsp;(<a href="#CITEREFKummer1836">1836</a>), and the fundamental characterisation by <a href="Bernhard_Riemann" title="Bernhard Riemann">Bernhard Riemann</a>&nbsp;(<a href="#CITEREFRiemann1857">1857</a>) of the hypergeometric function by means of the differential equation it satisfies.
</p><p>Riemann showed that the second-order differential equation for <sub>2</sub><i>F</i><sub>1</sub>(<i>z</i>), examined in the complex plane, could be characterised (on the <a href="Riemann_sphere" title="Riemann sphere">Riemann sphere</a>) by its three <a href="Regular_singularity" class="mw-redirect" title="Regular singularity">regular singularities</a>.
</p><p>The cases where the solutions are <a href="Algebraic_function" title="Algebraic function">algebraic functions</a> were found by <a href="Hermann_Schwarz" title="Hermann Schwarz">Hermann Schwarz</a> (<a href="Schwarz's_list" title="Schwarz's list">Schwarz's list</a>).
</p>
<div class="mw-heading mw-heading2"><h2 id="The_hypergeometric_series">The hypergeometric series</h2></div>
<p>The hypergeometric function is defined for <span class="texhtml">|<i>z</i>| &lt; 1</span> by the <a href="Power_series" title="Power series">power series</a>
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,b;c;z)=\sum _{n=0}^{\infty }{\frac {(a)_{n}(b)_{n}}{(c)_{n}}}{\frac {z^{n}}{n!}}=1+{\frac {ab}{c}}{\frac {z}{1!}}+{\frac {a(a+1)b(b+1)}{c(c+1)}}{\frac {z^{2}}{2!}}+\cdots .}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<munderover>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
</munderover>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>a</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>b</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
</mfrac>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
<mrow>
<mi>n</mi>
<mo>!</mo>
</mrow>
</mfrac>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>a</mi>
<mi>b</mi>
</mrow>
<mi>c</mi>
</mfrac>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>z</mi>
<mrow>
<mn>1</mn>
<mo>!</mo>
</mrow>
</mfrac>
</mrow>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>a</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mi>b</mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mrow>
<mn>2</mn>
<mo>!</mo>
</mrow>
</mfrac>
</mrow>
<mo>+</mo>
<mo>⋯<!-- ⋯ --></mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,b;c;z)=\sum _{n=0}^{\infty }{\frac {(a)_{n}(b)_{n}}{(c)_{n}}}{\frac {z^{n}}{n!}}=1+{\frac {ab}{c}}{\frac {z}{1!}}+{\frac {a(a+1)b(b+1)}{c(c+1)}}{\frac {z^{2}}{2!}}+\cdots .}</annotation>
</semantics>
</math></span></span>
</p><p>It is undefined (or infinite) if <span class="texhtml mvar" style="font-style:italic;">c</span> equals a non-positive <a href="Integer" title="Integer">integer</a>. Here <span class="texhtml">(<i>q</i>)<sub><i>n</i></sub></span> is the (rising) <a href="Pochhammer_symbol" class="mw-redirect" title="Pochhammer symbol">Pochhammer symbol</a>,<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>note 1<span class="cite-bracket">]</span></a></sup> which is defined by:
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (q)_{n}={\begin{cases}1&amp;n=0\\q(q+1)\cdots (q+n-1)&amp;n>0\end{cases}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>q</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mo>{</mo>
<mtable columnalign="left left" rowspacing=".2em" columnspacing="1em" displaystyle="false">
<mtr>
<mtd>
<mn>1</mn>
</mtd>
<mtd>
<mi>n</mi>
<mo>=</mo>
<mn>0</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mi>q</mi>
<mo stretchy="false">(</mo>
<mi>q</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>⋯<!-- ⋯ --></mo>
<mo stretchy="false">(</mo>
<mi>q</mi>
<mo>+</mo>
<mi>n</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi>n</mi>
<mo>&gt;</mo>
<mn>0</mn>
</mtd>
</mtr>
</mtable>
<mo fence="true" stretchy="true" symmetric="true"></mo>
</mrow>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (q)_{n}={\begin{cases}1&amp;n=0\\q(q+1)\cdots (q+n-1)&amp;n&gt;0\end{cases}}}</annotation>
</semantics>
</math></span></span>
</p><p>The series terminates if either <span class="texhtml mvar" style="font-style:italic;">a</span> or <span class="texhtml mvar" style="font-style:italic;">b</span> is a nonpositive integer, in which case the function reduces to a polynomial:
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(-m,b;c;z)=\sum _{n=0}^{m}(-1)^{n}{\binom {m}{n}}{\frac {(b)_{n}}{(c)_{n}}}z^{n}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mi>m</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<munderover>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
<mo>=</mo>
<mn>0</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
</mrow>
</munderover>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mrow class="MJX-TeXAtom-OPEN">
<mo maxsize="2.047em" minsize="2.047em">(</mo>
</mrow>
<mfrac linethickness="0">
<mi>m</mi>
<mi>n</mi>
</mfrac>
<mrow class="MJX-TeXAtom-CLOSE">
<mo maxsize="2.047em" minsize="2.047em">)</mo>
</mrow>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>b</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
</mfrac>
</mrow>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(-m,b;c;z)=\sum _{n=0}^{m}(-1)^{n}{\binom {m}{n}}{\frac {(b)_{n}}{(c)_{n}}}z^{n}.}</annotation>
</semantics>
</math></span></span>
</p><p>For complex arguments <span class="texhtml mvar" style="font-style:italic;">z</span> with <span class="texhtml">|<span class="nowrap" style="padding-left:0.1em; padding-right:0.1em;"><i>z</i></span>|&nbsp;≥&nbsp;1</span> it can be <a href="Analytic_continuation" title="Analytic continuation">analytically continued</a> along any path in the complex plane that avoids the branch points 1 and infinity. In practice, most computer implementations of the hypergeometric function adopt a branch cut along the line <span class="texhtml"><i>z</i>&nbsp;≥&nbsp;1</span>.
</p><p>As <span class="texhtml"><i>c</i> → −<i>m</i></span>, where <span class="texhtml mvar" style="font-style:italic;">m</span> is a non-negative integer, one has <span class="texhtml"><sub>2</sub><i>F</i><sub>1</sub>(<i>z</i>) → ∞</span>. Dividing by the value <span class="texhtml">Γ(<i>c</i>)</span> of the <a href="Gamma_function" title="Gamma function">gamma function</a>, we have the limit:
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lim _{c\to -m}{\frac {{}_{2}F_{1}(a,b;c;z)}{\Gamma (c)}}={\frac {(a)_{m+1}(b)_{m+1}}{(m+1)!}}z^{m+1}{}_{2}F_{1}(a+m+1,b+m+1;m+2;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<munder>
<mo movablelimits="true" form="prefix">lim</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo stretchy="false">→<!-- → --></mo>
<mo>−<!-- − --></mo>
<mi>m</mi>
</mrow>
</munder>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>a</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>b</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
</mrow>
</msub>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>!</mo>
</mrow>
</mfrac>
</mrow>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>m</mi>
<mo>+</mo>
<mn>2</mn>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \lim _{c\to -m}{\frac {{}_{2}F_{1}(a,b;c;z)}{\Gamma (c)}}={\frac {(a)_{m+1}(b)_{m+1}}{(m+1)!}}z^{m+1}{}_{2}F_{1}(a+m+1,b+m+1;m+2;z)}</annotation>
</semantics>
</math></span></span>
</p><p><span class="texhtml"><sub>2</sub><i>F</i><sub>1</sub>(<i>z</i>)</span> is the most common type of <a href="Generalized_hypergeometric_series" class="mw-redirect" title="Generalized hypergeometric series">generalized hypergeometric series</a> <span class="texhtml mvar" style="font-style:italic;"><sub>p</sub>F<sub>q</sub></span>, and is often designated simply <span class="texhtml"><i>F</i>(<i>z</i>)</span>.
</p>
<div class="mw-heading mw-heading2"><h2 id="Differentiation_formulas">Differentiation formulas</h2></div>
<p>Using the identity <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (a)_{n+1}=a(a+1)_{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>a</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
<mo>+</mo>
<mn>1</mn>
</mrow>
</msub>
<mo>=</mo>
<mi>a</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (a)_{n+1}=a(a+1)_{n}}</annotation>
</semantics>
</math></span><img src="./688b10013892901fee1768bf6b6a498f2d789c19.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.947ex; height:2.843ex;" alt="{\displaystyle (a)_{n+1}=a(a+1)_{n}}" loading="lazy"></span>, it is shown that
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {d}{dz}}\ {}_{2}F_{1}(a,b;c;z)={\frac {ab}{c}}\ {}_{2}F_{1}(a+1,b+1;c+1;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>d</mi>
<mrow>
<mi>d</mi>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
<mtext>&nbsp;</mtext>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>a</mi>
<mi>b</mi>
</mrow>
<mi>c</mi>
</mfrac>
</mrow>
<mtext>&nbsp;</mtext>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>c</mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {d}{dz}}\ {}_{2}F_{1}(a,b;c;z)={\frac {ab}{c}}\ {}_{2}F_{1}(a+1,b+1;c+1;z)}</annotation>
</semantics>
</math></span></span>
</p><p>and more generally,
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {d^{n}}{dz^{n}}}\ {}_{2}F_{1}(a,b;c;z)={\frac {(a)_{n}(b)_{n}}{(c)_{n}}}\ {}_{2}F_{1}(a+n,b+n;c+n;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<msup>
<mi>d</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
<mrow>
<mi>d</mi>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
<mtext>&nbsp;</mtext>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>a</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>b</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
</mfrac>
</mrow>
<mtext>&nbsp;</mtext>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>n</mi>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mi>n</mi>
<mo>;</mo>
<mi>c</mi>
<mo>+</mo>
<mi>n</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {d^{n}}{dz^{n}}}\ {}_{2}F_{1}(a,b;c;z)={\frac {(a)_{n}(b)_{n}}{(c)_{n}}}\ {}_{2}F_{1}(a+n,b+n;c+n;z)}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading2"><h2 id="Special_cases">Special cases</h2></div>
<p>Many of the common mathematical functions can be expressed in terms of the hypergeometric function, or as limiting cases of it. Some typical examples are
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}_{2}F_{1}\left(1,1;2;-z\right)&amp;={\frac {\ln(1+z)}{z}}\\_{2}F_{1}(a,b;b;z)&amp;=(1-z)^{-a}\quad (b{\text{ arbitrary}})\\_{2}F_{1}\left({\frac {1}{2}},{\frac {1}{2}};{\frac {3}{2}};z^{2}\right)&amp;={\frac {\arcsin(z)}{z}}\\\,_{2}F_{1}\left({\frac {1}{3}},{\frac {2}{3}};{\frac {3}{2}};-{\frac {27x^{2}}{4}}\right)&amp;={\frac {{\sqrt[{3}]{\frac {3x{\sqrt {3}}+{\sqrt {27x^{2}+4}}}{2}}}-{\sqrt[{3}]{\frac {2}{3x{\sqrt {3}}+{\sqrt {27x^{2}+4}}}}}}{x{\sqrt {3}}}}\\\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>,</mo>
<mn>1</mn>
<mo>;</mo>
<mn>2</mn>
<mo>;</mo>
<mo>−<!-- − --></mo>
<mi>z</mi>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>ln</mi>
<mo>⁡<!-- ⁡ --></mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
<mi>z</mi>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>b</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<mspace width="1em"></mspace>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mrow class="MJX-TeXAtom-ORD">
<mtext>&nbsp;arbitrary</mtext>
</mrow>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>3</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>arcsin</mi>
<mo>⁡<!-- ⁡ --></mo>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
<mi>z</mi>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>3</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>2</mn>
<mn>3</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>3</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>27</mn>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mn>4</mn>
</mfrac>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mroot>
<mfrac>
<mrow>
<mn>3</mn>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>3</mn>
</msqrt>
</mrow>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>27</mn>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>+</mo>
<mn>4</mn>
</msqrt>
</mrow>
</mrow>
<mn>2</mn>
</mfrac>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</mroot>
</mrow>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mroot>
<mfrac>
<mn>2</mn>
<mrow>
<mn>3</mn>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>3</mn>
</msqrt>
</mrow>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>27</mn>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>+</mo>
<mn>4</mn>
</msqrt>
</mrow>
</mrow>
</mfrac>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</mroot>
</mrow>
</mrow>
<mrow>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mn>3</mn>
</msqrt>
</mrow>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}_{2}F_{1}\left(1,1;2;-z\right)&amp;={\frac {\ln(1+z)}{z}}\\_{2}F_{1}(a,b;b;z)&amp;=(1-z)^{-a}\quad (b{\text{ arbitrary}})\\_{2}F_{1}\left({\frac {1}{2}},{\frac {1}{2}};{\frac {3}{2}};z^{2}\right)&amp;={\frac {\arcsin(z)}{z}}\\\,_{2}F_{1}\left({\frac {1}{3}},{\frac {2}{3}};{\frac {3}{2}};-{\frac {27x^{2}}{4}}\right)&amp;={\frac {{\sqrt[{3}]{\frac {3x{\sqrt {3}}+{\sqrt {27x^{2}+4}}}{2}}}-{\sqrt[{3}]{\frac {2}{3x{\sqrt {3}}+{\sqrt {27x^{2}+4}}}}}}{x{\sqrt {3}}}}\\\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>When <i>a</i>=1 and <i>b</i>=<i>c</i>, the series reduces into a plain <a href="Geometric_series" title="Geometric series">geometric series</a>, i.e.
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}_{2}F_{1}\left(1,b;b;z\right)&amp;={}_{1}F_{0}\left(1;;z\right)=1+z+z^{2}+z^{3}+z^{4}+\cdots \end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>b</mi>
<mo>;</mo>
<mi>z</mi>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>;</mo>
<mo>;</mo>
<mi>z</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<mo>+</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>+</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>+</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
<mo>+</mo>
<mo>⋯<!-- ⋯ --></mo>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}_{2}F_{1}\left(1,b;b;z\right)&amp;={}_{1}F_{0}\left(1;;z\right)=1+z+z^{2}+z^{3}+z^{4}+\cdots \end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>hence, the name <i>hypergeometric</i>. This function can be considered as a generalization of the <a href="Geometric_series" title="Geometric series">geometric series</a>.
</p><p>The <a href="Confluent_hypergeometric_function" title="Confluent hypergeometric function">confluent hypergeometric function</a> (or Kummer's function) can be given as a limit of the hypergeometric function
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle M(a,c,z)=\lim _{b\to \infty }{}_{2}F_{1}(a,b;c;b^{-1}z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>M</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>,</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<munder>
<mo movablelimits="true" form="prefix">lim</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>b</mi>
<mo stretchy="false">→<!-- → --></mo>
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
</munder>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<msup>
<mi>b</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</msup>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle M(a,c,z)=\lim _{b\to \infty }{}_{2}F_{1}(a,b;c;b^{-1}z)}</annotation>
</semantics>
</math></span></span>
</p><p>so all functions that are essentially special cases of it, such as <a href="Bessel_functions" class="mw-redirect" title="Bessel functions">Bessel functions</a>, can be expressed as limits of hypergeometric functions. These include most of the commonly used functions of mathematical physics.
</p><p><a href="Legendre_function" title="Legendre function">Legendre functions</a> are solutions of a second order differential equation with 3 regular singular points so can be expressed in terms of the hypergeometric function in many ways, for example
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,1-a;c;z)=\Gamma (c)z^{\tfrac {1-c}{2}}(1-z)^{\tfrac {c-1}{2}}P_{-a}^{1-c}(1-2z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
</mrow>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
</msup>
<msubsup>
<mi>P</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
</mrow>
</msubsup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,1-a;c;z)=\Gamma (c)z^{\tfrac {1-c}{2}}(1-z)^{\tfrac {c-1}{2}}P_{-a}^{1-c}(1-2z)}</annotation>
</semantics>
</math></span></span>
</p><p>Several orthogonal polynomials, including <a href="Jacobi_polynomials" title="Jacobi polynomials">Jacobi polynomials</a> <i>P</i><span class="nowrap"><span style="display:inline-block;margin-bottom:-0.3em;vertical-align:-0.4em;line-height:1.2em;font-size:80%;text-align:left"><sup style="font-size:inherit;line-height:inherit;vertical-align:baseline">(α,β)</sup><br><sub style="font-size:inherit;line-height:inherit;vertical-align:baseline"><i>n</i></sub></span></span> and their special cases <a href="Legendre_polynomials" title="Legendre polynomials">Legendre polynomials</a>, <a href="Chebyshev_polynomials" title="Chebyshev polynomials">Chebyshev polynomials</a>, <a href="Gegenbauer_polynomials" title="Gegenbauer polynomials">Gegenbauer polynomials</a>, <a href="Zernike_polynomials" title="Zernike polynomials">Zernike polynomials</a> can be written in terms of hypergeometric functions using
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(-n,\alpha +1+\beta +n;\alpha +1;x)={\frac {n!}{(\alpha +1)_{n}}}P_{n}^{(\alpha ,\beta )}(1-2x)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mi>n</mi>
<mo>,</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<mo>+</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<mi>n</mi>
<mo>;</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>n</mi>
<mo>!</mo>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
</mrow>
</mfrac>
</mrow>
<msubsup>
<mi>P</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>,</mo>
<mi>β<!-- β --></mi>
<mo stretchy="false">)</mo>
</mrow>
</msubsup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(-n,\alpha +1+\beta +n;\alpha +1;x)={\frac {n!}{(\alpha +1)_{n}}}P_{n}^{(\alpha ,\beta )}(1-2x)}</annotation>
</semantics>
</math></span></span>
</p><p>Other polynomials that are special cases include <a href="Krawtchouk_polynomials" class="mw-redirect" title="Krawtchouk polynomials">Krawtchouk polynomials</a>, <a href="Meixner_polynomials" title="Meixner polynomials">Meixner polynomials</a>, <a href="Meixner%E2%80%93Pollaczek_polynomials" title="Meixner–Pollaczek polynomials">Meixner–Pollaczek polynomials</a>.
</p><p>Given <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z\in \mathbb {C} \setminus \{0,1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>z</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">C</mi>
</mrow>
<mo class="MJX-variant">∖<!-- ∖ --></mo>
<mo fence="false" stretchy="false">{</mo>
<mn>0</mn>
<mo>,</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z\in \mathbb {C} \setminus \{0,1\}}</annotation>
</semantics>
</math></span><img src="./cceaeac856cd23c35a5bf78ff2f5d71f64a15021.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:13.485ex; height:2.843ex;" alt="{\displaystyle z\in \mathbb {C} \setminus \{0,1\}}" loading="lazy"></span>, let
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \tau ={\rm {i}}{\frac {{}_{2}F_{1}{\bigl (}{\frac {1}{2}},{\frac {1}{2}};1;1-z{\bigr )}}{{}_{2}F_{1}{\bigl (}{\frac {1}{2}},{\frac {1}{2}};1;z{\bigr )}}}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>τ<!-- τ --></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">i</mi>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-OPEN">
<mo maxsize="1.2em" minsize="1.2em">(</mo>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mn>1</mn>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-CLOSE">
<mo maxsize="1.2em" minsize="1.2em">)</mo>
</mrow>
</mrow>
</mrow>
<mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-OPEN">
<mo maxsize="1.2em" minsize="1.2em">(</mo>
</mrow>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mn>1</mn>
<mo>;</mo>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-CLOSE">
<mo maxsize="1.2em" minsize="1.2em">)</mo>
</mrow>
</mrow>
</mrow>
</mfrac>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \tau ={\rm {i}}{\frac {{}_{2}F_{1}{\bigl (}{\frac {1}{2}},{\frac {1}{2}};1;1-z{\bigr )}}{{}_{2}F_{1}{\bigl (}{\frac {1}{2}},{\frac {1}{2}};1;z{\bigr )}}}.}</annotation>
</semantics>
</math></span></span>
</p><p>Then
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lambda (\tau )={\frac {\theta _{2}(\tau )^{4}}{\theta _{3}(\tau )^{4}}}=z}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>λ<!-- λ --></mi>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msub>
<mi>θ<!-- θ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
</mrow>
<mrow>
<msub>
<mi>θ<!-- θ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
<mo>=</mo>
<mi>z</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \lambda (\tau )={\frac {\theta _{2}(\tau )^{4}}{\theta _{3}(\tau )^{4}}}=z}</annotation>
</semantics>
</math></span></span>
</p><p>is the <a href="Modular_lambda_function" title="Modular lambda function">modular lambda function</a>, where
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \theta _{2}(\tau )=\sum _{n\in \mathbb {Z} }e^{\pi i\tau (n+1/2)^{2}},\quad \theta _{3}(\tau )=\sum _{n\in \mathbb {Z} }e^{\pi i\tau n^{2}}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>θ<!-- θ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<munder>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
</mrow>
</munder>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>τ<!-- τ --></mi>
<mo stretchy="false">(</mo>
<mi>n</mi>
<mo>+</mo>
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>2</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</msup>
<mo>,</mo>
<mspace width="1em"></mspace>
<msub>
<mi>θ<!-- θ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<munder>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
</mrow>
</munder>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>τ<!-- τ --></mi>
<msup>
<mi>n</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</msup>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \theta _{2}(\tau )=\sum _{n\in \mathbb {Z} }e^{\pi i\tau (n+1/2)^{2}},\quad \theta _{3}(\tau )=\sum _{n\in \mathbb {Z} }e^{\pi i\tau n^{2}}.}</annotation>
</semantics>
</math></span></span>
</p><p>The <a href="J-invariant" title="J-invariant">j-invariant</a>, a <a href="Modular_form#Modular_functions" title="Modular form">modular function</a>, is a rational function in <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lambda (\tau )}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>λ<!-- λ --></mi>
<mo stretchy="false">(</mo>
<mi>τ<!-- τ --></mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \lambda (\tau )}</annotation>
</semantics>
</math></span><img src="./16ac1d81ccf9d599802d541a0be0aa1eea99ec7a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.366ex; height:2.843ex;" alt="{\displaystyle \lambda (\tau )}" loading="lazy"></span>.
</p><p><a href="Incomplete_beta_function" class="mw-redirect" title="Incomplete beta function">Incomplete beta functions</a> <i>B</i><sub><i>x</i></sub>(<i>p</i>,<i>q</i>) are related by
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle B_{x}(p,q)={\tfrac {x^{p}}{p}}{}_{2}F_{1}(p,1-q;p+1;x).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>B</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>x</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>p</mi>
<mo>,</mo>
<mi>q</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>p</mi>
</mrow>
</msup>
<mi>p</mi>
</mfrac>
</mstyle>
</mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>p</mi>
<mo>,</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>q</mi>
<mo>;</mo>
<mi>p</mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle B_{x}(p,q)={\tfrac {x^{p}}{p}}{}_{2}F_{1}(p,1-q;p+1;x).}</annotation>
</semantics>
</math></span></span>
</p><p>The <a href="Complete_elliptic_integral" class="mw-redirect" title="Complete elliptic integral">complete elliptic integrals</a> <i>K</i> and <i>E</i> are given by<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}K(k)&amp;={\tfrac {\pi }{2}}\,_{2}F_{1}\left({\tfrac {1}{2}},{\tfrac {1}{2}};1;k^{2}\right),\\E(k)&amp;={\tfrac {\pi }{2}}\,_{2}F_{1}\left(-{\tfrac {1}{2}},{\tfrac {1}{2}};1;k^{2}\right).\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<mi>K</mi>
<mo stretchy="false">(</mo>
<mi>k</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>π<!-- π --></mi>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mn>1</mn>
<mo>;</mo>
<msup>
<mi>k</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
<mo>,</mo>
</mtd>
</mtr>
<mtr>
<mtd>
<mi>E</mi>
<mo stretchy="false">(</mo>
<mi>k</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>π<!-- π --></mi>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mn>1</mn>
<mo>;</mo>
<msup>
<mi>k</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
<mo>.</mo>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}K(k)&amp;={\tfrac {\pi }{2}}\,_{2}F_{1}\left({\tfrac {1}{2}},{\tfrac {1}{2}};1;k^{2}\right),\\E(k)&amp;={\tfrac {\pi }{2}}\,_{2}F_{1}\left(-{\tfrac {1}{2}},{\tfrac {1}{2}};1;k^{2}\right).\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading2"><h2 id="The_hypergeometric_differential_equation">The hypergeometric differential equation</h2></div>
<p>The hypergeometric function is a solution of Euler's hypergeometric differential equation
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z(1-z){\frac {d^{2}w}{dz^{2}}}+\left[c-(a+b+1)z\right]{\frac {dw}{dz}}-ab\,w=0.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>z</mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msup>
<mi>d</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>w</mi>
</mrow>
<mrow>
<mi>d</mi>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
<mo>+</mo>
<mrow>
<mo>[</mo>
<mrow>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mi>z</mi>
</mrow>
<mo>]</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>d</mi>
<mi>w</mi>
</mrow>
<mrow>
<mi>d</mi>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mi>b</mi>
<mspace width="thinmathspace"></mspace>
<mi>w</mi>
<mo>=</mo>
<mn>0.</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z(1-z){\frac {d^{2}w}{dz^{2}}}+\left[c-(a+b+1)z\right]{\frac {dw}{dz}}-ab\,w=0.}</annotation>
</semantics>
</math></span></span>
</p><p>which has three <a href="Regular_singular_point" title="Regular singular point">regular singular points</a>: 0,1 and ∞. The generalization of this equation to three arbitrary regular singular points is given by <a href="Riemann's_differential_equation" title="Riemann's differential equation">Riemann's differential equation</a>. Any second order linear differential equation with three regular singular points can be converted to the hypergeometric differential equation by a change of variables.
</p>
<div class="mw-heading mw-heading3"><h3 id="Solutions_at_the_singular_points">Solutions at the singular points</h3></div>
<p>Solutions to the hypergeometric differential equation are built out of the hypergeometric series <sub>2</sub><i>F</i><sub>1</sub>(<i>a</i>,<i>b</i>;<i>c</i>;<i>z</i>). The equation has two <a href="Linearly_independent" class="mw-redirect" title="Linearly independent">linearly independent</a> solutions. At each of the three singular points 0, 1, ∞, there are usually two special solutions of the form <i>x</i><sup><i>s</i></sup> times a holomorphic function of <i>x</i>, where <i>s</i> is one of the two roots of the indicial equation and <i>x</i> is a local variable vanishing at a regular singular point. This gives 3&nbsp;×&nbsp;2&nbsp;=&nbsp;6 special solutions, as follows.
</p><p>Around the point <i>z</i>&nbsp;=&nbsp;0, two independent solutions are, if <i>c</i> is not a non-positive integer,
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \,_{2}F_{1}(a,b;c;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \,_{2}F_{1}(a,b;c;z)}</annotation>
</semantics>
</math></span></span>
</p><p>and, on condition that <i>c</i> is not an integer,
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z^{1-c}\,_{2}F_{1}(1+a-c,1+b-c;2-c;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
</mrow>
</msup>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>,</mo>
<mn>1</mn>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>2</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z^{1-c}\,_{2}F_{1}(1+a-c,1+b-c;2-c;z)}</annotation>
</semantics>
</math></span></span>
</p><p>If <i>c</i> is a non-positive integer 1−<i>m</i>, then the first of these solutions does not exist and must be replaced by <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z^{m}F(a+m,b+m;1+m;z).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
</mrow>
</msup>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>m</mi>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mi>m</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>m</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z^{m}F(a+m,b+m;1+m;z).}</annotation>
</semantics>
</math></span><img src="./9977d89e88e24439517dad53db7b143bde5cf7d4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:29.184ex; height:2.843ex;" alt="{\displaystyle z^{m}F(a+m,b+m;1+m;z).}" loading="lazy"></span> The second solution does not exist when <i>c</i> is an integer greater than 1, and is equal to the first solution, or its replacement, when <i>c</i> is any other integer. So when <i>c</i> is an integer, a more complicated expression must be used for a second solution, equal to the first solution multiplied by ln(<i>z</i>), plus another series in powers of <i>z</i>, involving the <a href="Digamma_function" title="Digamma function">digamma function</a>. See <a href="#CITEREFOlde_Daalhuis2010">Olde Daalhuis (2010)</a> for details.
</p><p>Around <i>z</i>&nbsp;=&nbsp;1, if <i>c</i>&nbsp;−&nbsp;<i>a</i>&nbsp;−&nbsp;<i>b</i> is not an integer, one has two independent solutions
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \,_{2}F_{1}(a,b;1+a+b-c;1-z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \,_{2}F_{1}(a,b;1+a+b-c;1-z)}</annotation>
</semantics>
</math></span></span>
</p><p>and
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (1-z)^{c-a-b}\;_{2}F_{1}(c-a,c-b;1+c-a-b;1-z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<msub>
<mspace width="thickmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (1-z)^{c-a-b}\;_{2}F_{1}(c-a,c-b;1+c-a-b;1-z)}</annotation>
</semantics>
</math></span></span>
</p><p>Around <i>z</i>&nbsp;=&nbsp;∞, if <i>a</i>&nbsp;−&nbsp;<i>b</i> is not an integer, one has two independent solutions
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z^{-a}\,_{2}F_{1}\left(a,1+a-c;1+a-b;z^{-1}\right)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z^{-a}\,_{2}F_{1}\left(a,1+a-c;1+a-b;z^{-1}\right)}</annotation>
</semantics>
</math></span></span>
</p><p>and
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z^{-b}\,_{2}F_{1}\left(b,1+b-c;1+b-a;z^{-1}\right).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>b</mi>
<mo>,</mo>
<mn>1</mn>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z^{-b}\,_{2}F_{1}\left(b,1+b-c;1+b-a;z^{-1}\right).}</annotation>
</semantics>
</math></span></span>
</p><p>Again, when the conditions of non-integrality are not met, there exist other solutions that are more complicated.
</p><p>Any 3 of the above 6 solutions satisfy a linear relation as the space of solutions is 2-dimensional, giving (<span class="nowrap"><span style="display:inline-block;margin-bottom:-0.3em;vertical-align:-0.4em;line-height:1.2em;font-size:80%;text-align:left"><sup style="font-size:inherit;line-height:inherit;vertical-align:baseline">6</sup><br><sub style="font-size:inherit;line-height:inherit;vertical-align:baseline">3</sub></span></span>) =&nbsp;20 linear relations between them called <b>connection formulas</b>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Kummer's_24_solutions">Kummer's 24 solutions</h3></div>
<p>A second order <a href="Fuchsian_equation" class="mw-redirect" title="Fuchsian equation">Fuchsian equation</a> with <i>n</i> singular points has a group of symmetries acting (projectively) on its solutions, isomorphic to the <a href="Coxeter_group" title="Coxeter group">Coxeter group</a> W(<i>D</i><sub><i>n</i></sub>) of order 2<sup><i>n</i>−1</sup><i>n</i>!. The hypergeometric equation is the case <i>n</i> = 3, with group of order 24 isomorphic to the symmetric group on 4 points, as first described by
<a href="Ernst_Kummer" title="Ernst Kummer">Kummer</a>. The appearance of the symmetric group is accidental and has no analogue for more than 3 singular points, and it is sometimes better to think of the group as an extension of the symmetric group on 3 points (acting as permutations of the 3 singular points) by a <a href="Klein_4-group" class="mw-redirect" title="Klein 4-group">Klein 4-group</a> (whose elements change the signs of the differences of the exponents at an even number of singular points). Kummer's group of 24 transformations is generated by the three transformations taking a solution <i>F</i>(<i>a</i>,<i>b</i>;<i>c</i>;<i>z</i>) to one of
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}(1-z)^{-a}F\left(a,c-b;c;{\tfrac {z}{z-1}}\right)\\F(a,b;1+a+b-c;1-z)\\(1-z)^{-b}F\left(c-a,b;c;{\tfrac {z}{z-1}}\right)\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<mi>F</mi>
<mrow>
<mo>(</mo>
<mrow>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}(1-z)^{-a}F\left(a,c-b;c;{\tfrac {z}{z-1}}\right)\\F(a,b;1+a+b-c;1-z)\\(1-z)^{-b}F\left(c-a,b;c;{\tfrac {z}{z-1}}\right)\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>which correspond to the transpositions (12), (23), and (34) under an isomorphism with the symmetric group on 4 points 1, 2, 3, 4. (The first and third of these are actually equal to <i>F</i>(<i>a</i>,<i>b</i>;<i>c</i>;<i>z</i>) whereas the second is an independent solution to the differential equation.)
</p><p>Applying Kummer's 24 = 6×4 transformations to the hypergeometric function gives the 6 = 2×3 solutions above corresponding to each of the 2 possible exponents at each of the 3 singular points, each of which appears 4 times because of the identities
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{c-a-b}\,{}_{2}F_{1}(c-a,c-b;c;z)&amp;&amp;{\text{Euler transformation}}\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-a}\,{}_{2}F_{1}(a,c-b;c;{\tfrac {z}{z-1}})&amp;&amp;{\text{Pfaff transformation}}\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-b}\,{}_{2}F_{1}(c-a,b;c;{\tfrac {z}{z-1}})&amp;&amp;{\text{Pfaff transformation}}\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd></mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mtext>Euler transformation</mtext>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">)</mo>
</mtd>
<mtd></mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mtext>Pfaff transformation</mtext>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">)</mo>
</mtd>
<mtd></mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mtext>Pfaff transformation</mtext>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{c-a-b}\,{}_{2}F_{1}(c-a,c-b;c;z)&amp;&amp;{\text{Euler transformation}}\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-a}\,{}_{2}F_{1}(a,c-b;c;{\tfrac {z}{z-1}})&amp;&amp;{\text{Pfaff transformation}}\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-b}\,{}_{2}F_{1}(c-a,b;c;{\tfrac {z}{z-1}})&amp;&amp;{\text{Pfaff transformation}}\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading3"><h3 id="Q-form">Q-form</h3></div>
<p>The hypergeometric differential equation may be brought into the Q-form
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {d^{2}u}{dz^{2}}}+Q(z)u(z)=0}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msup>
<mi>d</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mi>u</mi>
</mrow>
<mrow>
<mi>d</mi>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
<mo>+</mo>
<mi>Q</mi>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mi>u</mi>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mn>0</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {d^{2}u}{dz^{2}}}+Q(z)u(z)=0}</annotation>
</semantics>
</math></span></span>
</p><p>by making the substitution <i>u</i> = <i>wv</i> and eliminating the first-derivative term. One finds that
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Q={\frac {z^{2}[1-(a-b)^{2}]+z[2c(a+b-1)-4ab]+c(2-c)}{4z^{2}(1-z)^{2}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>Q</mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">[</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">]</mo>
<mo>+</mo>
<mi>z</mi>
<mo stretchy="false">[</mo>
<mn>2</mn>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mn>4</mn>
<mi>a</mi>
<mi>b</mi>
<mo stretchy="false">]</mo>
<mo>+</mo>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mn>2</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mn>4</mn>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle Q={\frac {z^{2}[1-(a-b)^{2}]+z[2c(a+b-1)-4ab]+c(2-c)}{4z^{2}(1-z)^{2}}}}</annotation>
</semantics>
</math></span></span>
</p><p>and <i>v</i> is given by the solution to
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {d}{dz}}\log v(z)=-{\frac {c-z(a+b+1)}{2z(1-z)}}=-{\frac {c}{2z}}-{\frac {1+a+b-c}{2(z-1)}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>d</mi>
<mrow>
<mi>d</mi>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
<mi>log</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>v</mi>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mn>2</mn>
<mi>z</mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>c</mi>
<mrow>
<mn>2</mn>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
</mrow>
<mrow>
<mn>2</mn>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {d}{dz}}\log v(z)=-{\frac {c-z(a+b+1)}{2z(1-z)}}=-{\frac {c}{2z}}-{\frac {1+a+b-c}{2(z-1)}}}</annotation>
</semantics>
</math></span></span>
</p><p>which is
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle v(z)=z^{-c/2}(1-z)^{(c-a-b-1)/2}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>v</mi>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>c</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>2</mn>
</mrow>
</msup>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle v(z)=z^{-c/2}(1-z)^{(c-a-b-1)/2}.}</annotation>
</semantics>
</math></span></span>
</p><p>The Q-form is significant in its relation to the <a href="Schwarzian_derivative" title="Schwarzian derivative">Schwarzian derivative</a> (<a href="#CITEREFHille1976">Hille 1976</a>, pp.&nbsp;307–401).
</p>
<div class="mw-heading mw-heading3"><h3 id="Schwarz_triangle_maps">Schwarz triangle maps</h3></div>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Schwarz_triangle_function" title="Schwarz triangle function">Schwarz triangle function</a></div>
<p>The <b>Schwarz triangle maps</b> or <b>Schwarz <i>s</i>-functions</b> are ratios of pairs of solutions.
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle s_{k}(z)={\frac {\phi _{k}^{(1)}(z)}{\phi _{k}^{(0)}(z)}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>k</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msubsup>
<mi>ϕ<!-- ϕ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>k</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</msubsup>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<msubsup>
<mi>ϕ<!-- ϕ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>k</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">(</mo>
<mn>0</mn>
<mo stretchy="false">)</mo>
</mrow>
</msubsup>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle s_{k}(z)={\frac {\phi _{k}^{(1)}(z)}{\phi _{k}^{(0)}(z)}}}</annotation>
</semantics>
</math></span></span>
</p><p>where <i>k</i> is one of the points 0, 1, ∞. The notation
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle D_{k}(\lambda ,\mu ,\nu ;z)=s_{k}(z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>D</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>k</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>λ<!-- λ --></mi>
<mo>,</mo>
<mi>μ<!-- μ --></mi>
<mo>,</mo>
<mi>ν<!-- ν --></mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<msub>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>k</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle D_{k}(\lambda ,\mu ,\nu ;z)=s_{k}(z)}</annotation>
</semantics>
</math></span></span>
</p><p>is also sometimes used. Note that the connection coefficients become <a href="M%C3%B6bius_transformation" title="Möbius transformation">Möbius transformations</a> on the triangle maps.
</p><p>Note that each triangle map is <a href="Regular_singular_point" title="Regular singular point">regular</a> at <i>z</i> ∈ {0, 1, ∞} respectively, with
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}s_{0}(z)&amp;=z^{\lambda }(1+{\mathcal {O}}(z))\\s_{1}(z)&amp;=(1-z)^{\mu }(1+{\mathcal {O}}(1-z))\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>λ<!-- λ --></mi>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-tex-caligraphic" mathvariant="script">O</mi>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>μ<!-- μ --></mi>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-tex-caligraphic" mathvariant="script">O</mi>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}s_{0}(z)&amp;=z^{\lambda }(1+{\mathcal {O}}(z))\\s_{1}(z)&amp;=(1-z)^{\mu }(1+{\mathcal {O}}(1-z))\end{aligned}}}</annotation>
</semantics>
</math></span></span>
and
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle s_{\infty }(z)=z^{\nu }(1+{\mathcal {O}}({\tfrac {1}{z}})).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>s</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>ν<!-- ν --></mi>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-tex-caligraphic" mathvariant="script">O</mi>
</mrow>
</mrow>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mi>z</mi>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle s_{\infty }(z)=z^{\nu }(1+{\mathcal {O}}({\tfrac {1}{z}})).}</annotation>
</semantics>
</math></span></span>
</p><p>In the special case of λ, μ and ν real, with 0&nbsp;≤&nbsp;λ,μ,ν&nbsp;&lt;&nbsp;1 then the s-maps are <a href="Conformal_map" title="Conformal map">conformal maps</a> of the <a href="Upper_half-plane" title="Upper half-plane">upper half-plane</a> <b>H</b> to triangles on the <a href="Riemann_sphere" title="Riemann sphere">Riemann sphere</a>, bounded by circular arcs. This mapping is <a href="Schwarzian_derivative#Conformal_mapping_of_circular_arc_polygons" title="Schwarzian derivative">a generalization</a> of the <a href="Schwarz%E2%80%93Christoffel_mapping" title="Schwarz–Christoffel mapping">Schwarz–Christoffel mapping</a> to triangles with circular arcs. The singular points 0,1 and ∞ are sent to the triangle vertices. The angles of the triangle are πλ, πμ and πν respectively.
</p><p>Furthermore, in the case of λ=1/<i>p</i>, μ=1/<i>q</i> and ν=1/<i>r</i> for integers <i>p</i>, <i>q</i>, <i>r</i>, then the triangle tiles the sphere, the complex plane or the upper half plane according to whether λ + μ + ν − 1 is positive, zero or negative; and the s-maps are inverse functions of <a href="Automorphic_function" title="Automorphic function">automorphic functions</a> for the <a href="Triangle_group" title="Triangle group">triangle group</a> 〈<i>p</i>,&nbsp;<i>q</i>,&nbsp;<i>r</i>〉&nbsp;=&nbsp;Δ(<i>p</i>,&nbsp;<i>q</i>,&nbsp;<i>r</i>).
</p>
<div class="mw-heading mw-heading3"><h3 id="Monodromy_group">Monodromy group</h3></div>
<p>The monodromy of a hypergeometric equation describes how fundamental solutions change when analytically continued around paths in the <i>z</i> plane that return to the same point.
That is, when the path winds around a singularity of <sub>2</sub><i>F</i><sub>1</sub>, the value of the solutions at the endpoint will differ from the starting point.
</p><p>Two fundamental solutions of the hypergeometric equation are related to each other by a linear transformation; thus the monodromy is a mapping (group homomorphism):
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \pi _{1}(\mathbf {C} \setminus \{0,1\},z_{0})\to {\text{GL}}(2,\mathbf {C} )}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>π<!-- π --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="bold">C</mi>
</mrow>
<mo class="MJX-variant">∖<!-- ∖ --></mo>
<mo fence="false" stretchy="false">{</mo>
<mn>0</mn>
<mo>,</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
<mo>,</mo>
<msub>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
</msub>
<mo stretchy="false">)</mo>
<mo stretchy="false">→<!-- → --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mtext>GL</mtext>
</mrow>
<mo stretchy="false">(</mo>
<mn>2</mn>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="bold">C</mi>
</mrow>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \pi _{1}(\mathbf {C} \setminus \{0,1\},z_{0})\to {\text{GL}}(2,\mathbf {C} )}</annotation>
</semantics>
</math></span></span>
</p><p>where π<sub>1</sub> is the <a href="Fundamental_group" title="Fundamental group">fundamental group</a>. In other words, the monodromy is a two dimensional linear representation of the fundamental group. The <a href="Monodromy_group" class="mw-redirect" title="Monodromy group">monodromy group</a> of the equation is the image of this map, i.e. the group generated by the monodromy matrices. The monodromy representation of the fundamental group can be computed explicitly in terms of the exponents at the singular points.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> If (α, α'), (β, β') and (γ,γ') are the exponents at 0, 1 and ∞, then, taking <i>z</i><sub>0</sub> near 0, the loops around 0 and 1 have monodromy matrices
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}g_{0}&amp;={\begin{pmatrix}e^{2\pi i\alpha }&amp;0\\0&amp;e^{2\pi i\alpha ^{\prime }}\end{pmatrix}}\\g_{1}&amp;={\begin{pmatrix}{\mu e^{2\pi i\beta }-e^{2\pi i\beta ^{\prime }} \over \mu -1}&amp;{\mu (e^{2\pi i\beta }-e^{2\pi i\beta ^{\prime }}) \over (\mu -1)^{2}}\\e^{2\pi i\beta ^{\prime }}-e^{2\pi i\beta }&amp;{\mu e^{2\pi i\beta ^{\prime }}-e^{2\pi i\beta } \over \mu -1}\end{pmatrix}},\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mi>g</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
</msub>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mo>(</mo>
<mtable rowspacing="4pt" columnspacing="1em">
<mtr>
<mtd>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>α<!-- α --></mi>
</mrow>
</msup>
</mtd>
<mtd>
<mn>0</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mn>0</mn>
</mtd>
<mtd>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<msup>
<mi>α<!-- α --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
</mrow>
</msup>
</mtd>
</mtr>
</mtable>
<mo>)</mo>
</mrow>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mi>g</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mo>(</mo>
<mtable rowspacing="4pt" columnspacing="1em">
<mtr>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>μ<!-- μ --></mi>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>β<!-- β --></mi>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
</mrow>
</msup>
</mrow>
<mrow>
<mi>μ<!-- μ --></mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mrow>
</mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>μ<!-- μ --></mi>
<mo stretchy="false">(</mo>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>β<!-- β --></mi>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
</mrow>
</msup>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>μ<!-- μ --></mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>β<!-- β --></mi>
</mrow>
</msup>
</mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>μ<!-- μ --></mi>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<msup>
<mi>e</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
<mi>β<!-- β --></mi>
</mrow>
</msup>
</mrow>
<mrow>
<mi>μ<!-- μ --></mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>)</mo>
</mrow>
</mrow>
<mo>,</mo>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}g_{0}&amp;={\begin{pmatrix}e^{2\pi i\alpha }&amp;0\\0&amp;e^{2\pi i\alpha ^{\prime }}\end{pmatrix}}\\g_{1}&amp;={\begin{pmatrix}{\mu e^{2\pi i\beta }-e^{2\pi i\beta ^{\prime }} \over \mu -1}&amp;{\mu (e^{2\pi i\beta }-e^{2\pi i\beta ^{\prime }}) \over (\mu -1)^{2}}\\e^{2\pi i\beta ^{\prime }}-e^{2\pi i\beta }&amp;{\mu e^{2\pi i\beta ^{\prime }}-e^{2\pi i\beta } \over \mu -1}\end{pmatrix}},\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>where
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mu ={\sin \pi (\alpha +\beta ^{\prime }+\gamma ^{\prime })\sin \pi (\alpha ^{\prime }+\beta +\gamma ^{\prime }) \over \sin \pi (\alpha ^{\prime }+\beta ^{\prime }+\gamma ^{\prime })\sin \pi (\alpha +\beta +\gamma ^{\prime })}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>μ<!-- μ --></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>sin</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>π<!-- π --></mi>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo>+</mo>
<msup>
<mi>γ<!-- γ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo stretchy="false">)</mo>
<mi>sin</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>π<!-- π --></mi>
<mo stretchy="false">(</mo>
<msup>
<mi>α<!-- α --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo>+</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<msup>
<mi>γ<!-- γ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi>sin</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>π<!-- π --></mi>
<mo stretchy="false">(</mo>
<msup>
<mi>α<!-- α --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo>+</mo>
<msup>
<mi>β<!-- β --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo>+</mo>
<msup>
<mi>γ<!-- γ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo stretchy="false">)</mo>
<mi>sin</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>π<!-- π --></mi>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<msup>
<mi>γ<!-- γ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mi class="MJX-variant" mathvariant="normal">′<!-- ′ --></mi>
</mrow>
</msup>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mu ={\sin \pi (\alpha +\beta ^{\prime }+\gamma ^{\prime })\sin \pi (\alpha ^{\prime }+\beta +\gamma ^{\prime }) \over \sin \pi (\alpha ^{\prime }+\beta ^{\prime }+\gamma ^{\prime })\sin \pi (\alpha +\beta +\gamma ^{\prime })}.}</annotation>
</semantics>
</math></span></span>
</p><p>If 1−<i>a</i>, <i>c</i>−<i>a</i>−<i>b</i>, <i>a</i>−<i>b</i> are non-integer <a href="Rational_number" title="Rational number">rational numbers</a> with denominators <i>k</i>,<i>l</i>,<i>m</i> then the monodromy group is finite <a href="If_and_only_if" title="If and only if">if and only if</a> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1/k+1/l+1/m>1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>k</mi>
<mo>+</mo>
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>l</mi>
<mo>+</mo>
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>m</mi>
<mo>&gt;</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle 1/k+1/l+1/m&gt;1}</annotation>
</semantics>
</math></span><img src="./3e5ff7d616b6e543dc3e76432015e8cf836881c3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:20.861ex; height:2.843ex;" alt="{\displaystyle 1/k+1/l+1/m>1}" loading="lazy"></span>, see <a href="Schwarz's_list" title="Schwarz's list">Schwarz's list</a> or <a href="Picard%E2%80%93Vessiot_theory" title="Picard–Vessiot theory">Kovacic's algorithm</a>.
</p>
<div class="mw-heading mw-heading2"><h2 id="Integral_formulas">Integral formulas</h2></div>
<div class="mw-heading mw-heading3"><h3 id="Euler_type">Euler type</h3></div>
<p>If <i>B</i> is the <a href="Beta_function" title="Beta function">beta function</a> then
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {B} (b,c-b)\,_{2}F_{1}(a,b;c;z)=\int _{0}^{1}x^{b-1}(1-x)^{c-b-1}(1-zx)^{-a}\,dx\qquad \Re (c)>\Re (b)>0,}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="normal">B</mi>
</mrow>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<msubsup>
<mo>∫<!-- ∫ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>0</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msubsup>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>b</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>x</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mi>x</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<mi>d</mi>
<mi>x</mi>
<mspace width="2em"></mspace>
<mi mathvariant="normal">ℜ<!-- ℜ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mo>&gt;</mo>
<mi mathvariant="normal">ℜ<!-- ℜ --></mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<mo>&gt;</mo>
<mn>0</mn>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathrm {B} (b,c-b)\,_{2}F_{1}(a,b;c;z)=\int _{0}^{1}x^{b-1}(1-x)^{c-b-1}(1-zx)^{-a}\,dx\qquad \Re (c)&gt;\Re (b)&gt;0,}</annotation>
</semantics>
</math></span></span>
</p><p>provided that <i>z</i> is not a real number such that it is greater than or equal to 1. This can be proved by expanding (1&nbsp;−&nbsp;<i>zx</i>)<sup>−<i>a</i></sup> using the <a href="Binomial_theorem" title="Binomial theorem">binomial theorem</a> and then integrating term by term for <i>z</i> with absolute value smaller than 1, and by analytic continuation elsewhere. When <i>z</i> is a real number greater than or equal to 1, analytic continuation must be used, because (1&nbsp;−&nbsp;<i>zx</i>) is zero at some point in the support of the integral, so the value of the integral may be ill-defined. This was given by Euler in 1748 and implies <a href="Binomial_transform#Euler_transform" title="Binomial transform">Euler's</a> and Pfaff's hypergeometric transformations.
</p><p>Other representations, corresponding to other <a href="Principal_branch" title="Principal branch">branches</a>, are given by taking the same integrand, but taking the path of integration to be a closed <a href="Pochhammer_cycle" class="mw-redirect" title="Pochhammer cycle">Pochhammer cycle</a> enclosing the singularities in various orders. Such paths correspond to the <a href="Monodromy" title="Monodromy">monodromy</a> action.
</p>
<div class="mw-heading mw-heading3"><h3 id="Barnes_integral">Barnes integral</h3></div>
<p>Barnes used the theory of <a href="Residue_(complex_analysis)" title="Residue (complex analysis)">residues</a> to evaluate the <a href="Barnes_integral" title="Barnes integral">Barnes integral</a>
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {1}{2\pi i}}\int _{-i\infty }^{i\infty }{\frac {\Gamma (a+s)\Gamma (b+s)\Gamma (-s)}{\Gamma (c+s)}}(-z)^{s}\,ds}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mn>1</mn>
<mrow>
<mn>2</mn>
<mi>π<!-- π --></mi>
<mi>i</mi>
</mrow>
</mfrac>
</mrow>
<msubsup>
<mo>∫<!-- ∫ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>i</mi>
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mrow>
</msubsup>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>s</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>+</mo>
<mi>s</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mi>s</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mi>s</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>s</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<mi>d</mi>
<mi>s</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {1}{2\pi i}}\int _{-i\infty }^{i\infty }{\frac {\Gamma (a+s)\Gamma (b+s)\Gamma (-s)}{\Gamma (c+s)}}(-z)^{s}\,ds}</annotation>
</semantics>
</math></span></span>
</p><p>as
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {\Gamma (a)\Gamma (b)}{\Gamma (c)}}\,_{2}F_{1}(a,b;c;z),}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {\Gamma (a)\Gamma (b)}{\Gamma (c)}}\,_{2}F_{1}(a,b;c;z),}</annotation>
</semantics>
</math></span></span>
</p><p>where the contour is drawn to separate the poles 0, 1, 2... from the poles −<i>a</i>, −<i>a</i>&nbsp;−&nbsp;1,&nbsp;..., −<i>b</i>, −<i>b</i>&nbsp;−&nbsp;1,&nbsp;...&nbsp;. This is valid as long as z is not a nonnegative real number.
</p>
<div class="mw-heading mw-heading3"><h3 id="John_transform">John transform</h3></div>
<p>The Gauss hypergeometric function can be written as a <a href="John_transform" class="mw-redirect" title="John transform">John transform</a> (<a href="#CITEREFGelfandGindikinGraev2003">Gelfand, Gindikin &amp; Graev 2003</a>, 2.1.2).
</p>
<div class="mw-heading mw-heading2"><h2 id="Gauss's_contiguous_relations">Gauss's contiguous relations</h2></div>
<p>The six functions
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a\pm 1,b;c;z),\quad {}_{2}F_{1}(a,b\pm 1;c;z),\quad {}_{2}F_{1}(a,b;c\pm 1;z)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>±<!-- ± --></mo>
<mn>1</mn>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
<mspace width="1em"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>±<!-- ± --></mo>
<mn>1</mn>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
<mspace width="1em"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>±<!-- ± --></mo>
<mn>1</mn>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a\pm 1,b;c;z),\quad {}_{2}F_{1}(a,b\pm 1;c;z),\quad {}_{2}F_{1}(a,b;c\pm 1;z)}</annotation>
</semantics>
</math></span></span>
</p><p>are called contiguous to <span class="texhtml"><sub>2</sub><i>F</i><sub>1</sub>(<i>a</i>, <i>b</i>; <i>c</i>; <i>z</i>)</span>. Gauss showed that <span class="texhtml"><sub>2</sub><i>F</i><sub>1</sub>(<i>a</i>, <i>b</i>; <i>c</i>; <i>z</i>)</span> can be written as a linear combination of any two of its contiguous functions, with rational coefficients in terms of <span class="texhtml"><i>a</i>, <i>b</i>, <i>c</i></span>, and <span class="texhtml mvar" style="font-style:italic;">z</span>. This gives
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{pmatrix}6\\2\end{pmatrix}}=15}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mo>(</mo>
<mtable rowspacing="4pt" columnspacing="1em">
<mtr>
<mtd>
<mn>6</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mn>2</mn>
</mtd>
</mtr>
</mtable>
<mo>)</mo>
</mrow>
</mrow>
<mo>=</mo>
<mn>15</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{pmatrix}6\\2\end{pmatrix}}=15}</annotation>
</semantics>
</math></span></span>
</p><p>relations, given by identifying any two lines on the right hand side of
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}z{\frac {dF}{dz}}&amp;=z{\frac {ab}{c}}F(a+,b+,c+)\\&amp;=a(F(a+)-F)\\&amp;=b(F(b+)-F)\\&amp;=(c-1)(F(c-)-F)\\&amp;={\frac {(c-a)F(a-)+(a-c+bz)F}{1-z}}\\&amp;={\frac {(c-b)F(b-)+(b-c+az)F}{1-z}}\\&amp;=z{\frac {(c-a)(c-b)F(c+)+c(a+b-c)F}{c(1-z)}}\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>d</mi>
<mi>F</mi>
</mrow>
<mrow>
<mi>d</mi>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>a</mi>
<mi>b</mi>
</mrow>
<mi>c</mi>
</mfrac>
</mrow>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mo>,</mo>
<mi>c</mi>
<mo>+</mo>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mi>a</mi>
<mo stretchy="false">(</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mi>F</mi>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mi>b</mi>
<mo stretchy="false">(</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>+</mo>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mi>F</mi>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mi>F</mi>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mo stretchy="false">)</mo>
<mo>+</mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>+</mo>
<mi>b</mi>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
</mrow>
<mrow>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mo stretchy="false">)</mo>
<mo>+</mo>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>+</mo>
<mi>a</mi>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
</mrow>
<mrow>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mo stretchy="false">)</mo>
<mo>+</mo>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi>F</mi>
</mrow>
<mrow>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}z{\frac {dF}{dz}}&amp;=z{\frac {ab}{c}}F(a+,b+,c+)\\&amp;=a(F(a+)-F)\\&amp;=b(F(b+)-F)\\&amp;=(c-1)(F(c-)-F)\\&amp;={\frac {(c-a)F(a-)+(a-c+bz)F}{1-z}}\\&amp;={\frac {(c-b)F(b-)+(b-c+az)F}{1-z}}\\&amp;=z{\frac {(c-a)(c-b)F(c+)+c(a+b-c)F}{c(1-z)}}\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>where <span class="texhtml"><i>F</i> = <sub>2</sub><i>F</i><sub>1</sub>(<i>a</i>, <i>b</i>; <i>c</i>; <i>z</i>), <i>F</i>(<i>a</i>+) = <sub>2</sub><i>F</i><sub>1</sub>(<i>a</i> + 1, <i>b</i>; <i>c</i>; <i>z</i>)</span>, and so on. Repeatedly applying these relations gives a linear relation over <span class="texhtml"><b>C</b>(z)</span> between any three functions of the form
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a+m,b+n;c+l;z),}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>m</mi>
<mo>,</mo>
<mi>b</mi>
<mo>+</mo>
<mi>n</mi>
<mo>;</mo>
<mi>c</mi>
<mo>+</mo>
<mi>l</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a+m,b+n;c+l;z),}</annotation>
</semantics>
</math></span></span>
</p><p>where <i>m</i>, <i>n</i>, and <i>l</i> are integers.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading3"><h3 id="Gauss's_continued_fraction">Gauss's continued fraction</h3></div>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Gauss_continued_fraction" class="mw-redirect" title="Gauss continued fraction">Gauss continued fraction</a></div>
<p>Gauss used the contiguous relations to give several ways to write a quotient of two hypergeometric functions as a continued fraction, for example:
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {{}_{2}F_{1}(a+1,b;c+1;z)}{{}_{2}F_{1}(a,b;c;z)}}={\cfrac {1}{1+{\cfrac {{\frac {(a-c)b}{c(c+1)}}z}{1+{\cfrac {{\frac {(b-c-1)(a+1)}{(c+1)(c+2)}}z}{1+{\cfrac {{\frac {(a-c-1)(b+1)}{(c+2)(c+3)}}z}{1+{\cfrac {{\frac {(b-c-2)(a+2)}{(c+3)(c+4)}}z}{1+{}\ddots }}}}}}}}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>+</mo>
<mn>1</mn>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</mstyle>
</mrow>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi>b</mi>
</mrow>
<mrow>
<mi>c</mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mi>z</mi>
</mrow>
</mstyle>
</mrow>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mi>z</mi>
</mrow>
</mstyle>
</mrow>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>3</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mi>z</mi>
</mrow>
</mstyle>
</mrow>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>3</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>+</mo>
<mn>4</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mi>z</mi>
</mrow>
</mstyle>
</mrow>
<mrow>
<mpadded width="0" height="8.6pt" depth="3pt">
<mrow></mrow>
</mpadded>
<mstyle displaystyle="false" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mo>⋱<!-- ⋱ --></mo>
</mrow>
</mstyle>
</mrow>
</mfrac>
</mrow>
</mrow>
</mstyle>
</mrow>
</mfrac>
</mrow>
</mrow>
</mstyle>
</mrow>
</mfrac>
</mrow>
</mrow>
</mstyle>
</mrow>
</mfrac>
</mrow>
</mrow>
</mstyle>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\frac {{}_{2}F_{1}(a+1,b;c+1;z)}{{}_{2}F_{1}(a,b;c;z)}}={\cfrac {1}{1+{\cfrac {{\frac {(a-c)b}{c(c+1)}}z}{1+{\cfrac {{\frac {(b-c-1)(a+1)}{(c+1)(c+2)}}z}{1+{\cfrac {{\frac {(a-c-1)(b+1)}{(c+2)(c+3)}}z}{1+{\cfrac {{\frac {(b-c-2)(a+2)}{(c+3)(c+4)}}z}{1+{}\ddots }}}}}}}}}}}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading2"><h2 id="Transformation_formulas">Transformation formulas</h2></div>
<p>Transformation formulas relate two hypergeometric functions at different values of the argument <i>z</i>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Fractional_linear_transformations">Fractional linear transformations</h3></div>
<p>Euler's transformation is
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,b;c;z)=(1-z)^{c-a-b}{}_{2}F_{1}(c-a,c-b;c;z).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,b;c;z)=(1-z)^{c-a-b}{}_{2}F_{1}(c-a,c-b;c;z).}</annotation>
</semantics>
</math></span></span>
It follows by combining the two Pfaff transformations
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-b}{}_{2}F_{1}\left(b,c-a;c;{\tfrac {z}{z-1}}\right)\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-a}{}_{2}F_{1}\left(a,c-b;c;{\tfrac {z}{z-1}}\right)\\\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>b</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mi>z</mi>
<mrow>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-b}{}_{2}F_{1}\left(b,c-a;c;{\tfrac {z}{z-1}}\right)\\{}_{2}F_{1}(a,b;c;z)&amp;=(1-z)^{-a}{}_{2}F_{1}\left(a,c-b;c;{\tfrac {z}{z-1}}\right)\\\end{aligned}}}</annotation>
</semantics>
</math></span></span>
which in turn follow from Euler's integral representation. For extension of Euler's first and second transformations, see <a href="#CITEREFRathieParis2007">Rathie &amp; Paris (2007)</a> and <a href="#CITEREFRakhaRathie2011">Rakha &amp; Rathie (2011)</a>.
It can also be written as linear combination
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c,z)={}&amp;{\frac {\Gamma (c)\Gamma (c-a-b)}{\Gamma (c-a)\Gamma (c-b)}}{}_{2}F_{1}(a,b;a+b+1-c;1-z)\\[6pt]&amp;{}+{\frac {\Gamma (c)\Gamma (a+b-c)}{\Gamma (a)\Gamma (b)}}(1-z)^{c-a-b}{}_{2}F_{1}(c-a,c-b;1+c-a-b;1-z).\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="0.9em 0.3em" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>,</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
</mtd>
<mtd>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>+</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>,</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}{}_{2}F_{1}(a,b;c,z)={}&amp;{\frac {\Gamma (c)\Gamma (c-a-b)}{\Gamma (c-a)\Gamma (c-b)}}{}_{2}F_{1}(a,b;a+b+1-c;1-z)\\[6pt]&amp;{}+{\frac {\Gamma (c)\Gamma (a+b-c)}{\Gamma (a)\Gamma (b)}}(1-z)^{c-a-b}{}_{2}F_{1}(c-a,c-b;1+c-a-b;1-z).\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading3"><h3 id="Quadratic_transformations">Quadratic transformations</h3></div>
<p>If two of the numbers 1&nbsp;−&nbsp;<i>c</i>, <i>c</i>&nbsp;−&nbsp;1, <i>a</i>&nbsp;−&nbsp;<i>b</i>, <i>b</i>&nbsp;−&nbsp;<i>a</i>, <i>a</i>&nbsp;+&nbsp;<i>b</i>&nbsp;−&nbsp;<i>c</i>, <i>c</i>&nbsp;−&nbsp;<i>a</i>&nbsp;−&nbsp;<i>b</i> are equal or one of them is 1/2 then there is a <b>quadratic transformation</b> of the hypergeometric function, connecting it to a different value of <i>z</i> related by a quadratic equation. The first examples were given by <a href="#CITEREFKummer1836">Kummer (1836)</a>, and a complete list was given by <a href="#CITEREFGoursat1881">Goursat (1881)</a>. A typical example is
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,b;2b;z)=(1-z)^{-{\frac {a}{2}}}{}_{2}F_{1}\left({\tfrac {1}{2}}a,b-{\tfrac {1}{2}}a;b+{\tfrac {1}{2}};{\frac {z^{2}}{4z-4}}\right)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mn>2</mn>
<mi>b</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>a</mi>
<mn>2</mn>
</mfrac>
</mrow>
</mrow>
</msup>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>a</mi>
<mo>;</mo>
<mi>b</mi>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mrow>
<mn>4</mn>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>4</mn>
</mrow>
</mfrac>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,b;2b;z)=(1-z)^{-{\frac {a}{2}}}{}_{2}F_{1}\left({\tfrac {1}{2}}a,b-{\tfrac {1}{2}}a;b+{\tfrac {1}{2}};{\frac {z^{2}}{4z-4}}\right)}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading3"><h3 id="Higher_order_transformations">Higher order transformations</h3></div>
<p>If 1−<i>c</i>, <i>a</i>−<i>b</i>, <i>a</i>+<i>b</i>−<i>c</i> differ by signs or two of them are 1/3 or −1/3 then there is a <b>cubic transformation</b> of the hypergeometric function, connecting it to a different value of <i>z</i> related by a cubic equation. The first examples were given by <a href="#CITEREFGoursat1881">Goursat (1881)</a>. A typical example is
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}\left({\tfrac {3}{2}}a,{\tfrac {1}{2}}(3a-1);a+{\tfrac {1}{2}};-{\tfrac {z^{2}}{3}}\right)=(1+z)^{1-3a}\,{}_{2}F_{1}\left(a-{\tfrac {1}{3}},a;2a;2z(3+z^{2})(1+z)^{-3}\right)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>3</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>a</mi>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">(</mo>
<mn>3</mn>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>;</mo>
<mi>a</mi>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mn>3</mn>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mo>−<!-- − --></mo>
<mn>3</mn>
<mi>a</mi>
</mrow>
</msup>
<mspace width="thinmathspace"></mspace>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>3</mn>
</mfrac>
</mstyle>
</mrow>
<mo>,</mo>
<mi>a</mi>
<mo>;</mo>
<mn>2</mn>
<mi>a</mi>
<mo>;</mo>
<mn>2</mn>
<mi>z</mi>
<mo stretchy="false">(</mo>
<mn>3</mn>
<mo>+</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mn>3</mn>
</mrow>
</msup>
</mrow>
<mo>)</mo>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}\left({\tfrac {3}{2}}a,{\tfrac {1}{2}}(3a-1);a+{\tfrac {1}{2}};-{\tfrac {z^{2}}{3}}\right)=(1+z)^{1-3a}\,{}_{2}F_{1}\left(a-{\tfrac {1}{3}},a;2a;2z(3+z^{2})(1+z)^{-3}\right)}</annotation>
</semantics>
</math></span></span>
</p><p>There are also some transformations of degree 4 and 6. Transformations of other degrees only exist if <i>a</i>, <i>b</i>, and <i>c</i> are certain rational numbers (<a href="#CITEREFVidunas2005">Vidunas 2005</a>). For example,
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}\left({\tfrac {1}{4}},{\tfrac {3}{8}};{\tfrac {7}{8}};z\right)(z^{4}-60z^{3}+134z^{2}-60z+1)^{1/16}={}_{2}F_{1}\left({\tfrac {1}{48}},{\tfrac {17}{48}};{\tfrac {7}{8}};{\tfrac {-432z(z-1)^{2}(z+1)^{8}}{(z^{4}-60z^{3}+134z^{2}-60z+1)^{3}}}\right).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>4</mn>
</mfrac>
</mstyle>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>3</mn>
<mn>8</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>7</mn>
<mn>8</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mi>z</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">(</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>60</mn>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>+</mo>
<mn>134</mn>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>60</mn>
<mi>z</mi>
<mo>+</mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>16</mn>
</mrow>
</msup>
<mo>=</mo>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>48</mn>
</mfrac>
</mstyle>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>17</mn>
<mn>48</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>7</mn>
<mn>8</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mo>−<!-- − --></mo>
<mn>432</mn>
<mi>z</mi>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo stretchy="false">(</mo>
<mi>z</mi>
<mo>+</mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>8</mn>
</mrow>
</msup>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>4</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>60</mn>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>+</mo>
<mn>134</mn>
<msup>
<mi>z</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>60</mn>
<mi>z</mi>
<mo>+</mo>
<mn>1</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}\left({\tfrac {1}{4}},{\tfrac {3}{8}};{\tfrac {7}{8}};z\right)(z^{4}-60z^{3}+134z^{2}-60z+1)^{1/16}={}_{2}F_{1}\left({\tfrac {1}{48}},{\tfrac {17}{48}};{\tfrac {7}{8}};{\tfrac {-432z(z-1)^{2}(z+1)^{8}}{(z^{4}-60z^{3}+134z^{2}-60z+1)^{3}}}\right).}</annotation>
</semantics>
</math></span></span>
</p>
<div class="mw-heading mw-heading2"><h2 id="Values_at_special_points_z">Values at special points <i>z</i></h2></div>
<p>See <a href="#CITEREFSlater1966">Slater (1966</a>, Appendix III) for a list of summation formulas at special points, most of which also appear in <a href="#CITEREFBailey1935">Bailey (1935)</a>. <a href="#CITEREFGesselStanton1982">Gessel &amp; Stanton (1982)</a> gives further evaluations at more points. <a href="#CITEREFKoepf1995">Koepf (1995)</a> shows how most of these identities can be verified by computer algorithms.
</p>
<div class="mw-heading mw-heading3"><h3 id="Special_values_at_z_=_1">Special values at <i>z</i>&nbsp;=&nbsp;1</h3></div>
<p>Gauss's summation theorem, named for <a href="Carl_Friedrich_Gauss" title="Carl Friedrich Gauss">Carl Friedrich Gauss</a>, is the identity
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,b;c;1)={\frac {\Gamma (c)\Gamma (c-a-b)}{\Gamma (c-a)\Gamma (c-b)}},\qquad \Re (c)>\Re (a+b)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>,</mo>
<mspace width="2em"></mspace>
<mi mathvariant="normal">ℜ<!-- ℜ --></mi>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mo>&gt;</mo>
<mi mathvariant="normal">ℜ<!-- ℜ --></mi>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,b;c;1)={\frac {\Gamma (c)\Gamma (c-a-b)}{\Gamma (c-a)\Gamma (c-b)}},\qquad \Re (c)&gt;\Re (a+b)}</annotation>
</semantics>
</math></span></span>
</p><p>which follows from Euler's integral formula by putting <i>z</i>&nbsp;=&nbsp;1. It includes the <a href="Vandermonde_identity" class="mw-redirect" title="Vandermonde identity">Vandermonde identity</a> as a special case.
</p><p>For the special case where <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a=-m}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>a</mi>
<mo>=</mo>
<mo>−<!-- − --></mo>
<mi>m</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle a=-m}</annotation>
</semantics>
</math></span><img src="./88c31c0acca3b4971a3f929bfe57835bf8f8ce4b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:8.177ex; height:2.176ex;" alt="{\displaystyle a=-m}" loading="lazy"></span>,
<span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(-m,b;c;1)={\frac {(c-b)_{m}}{(c)_{m}}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mi>m</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
</mrow>
</msub>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mi>c</mi>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
</mrow>
</msub>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(-m,b;c;1)={\frac {(c-b)_{m}}{(c)_{m}}}}</annotation>
</semantics>
</math></span></span>
</p><p><a href="Bilateral_hypergeometric_series" title="Bilateral hypergeometric series">Dougall's formula</a> generalizes this to the <a href="Bilateral_hypergeometric_series" title="Bilateral hypergeometric series">bilateral hypergeometric series</a> at <i>z</i>&nbsp;=&nbsp;1.
</p>
<div class="mw-heading mw-heading3"><h3 id="Kummer's_theorem_(z_=_−1)">Kummer's theorem (<i>z</i>&nbsp;=&nbsp;−1)</h3></div>
<p>There are many cases where hypergeometric functions can be evaluated at <i>z</i>&nbsp;=&nbsp;−1 by using a quadratic transformation to change <i>z</i>&nbsp;=&nbsp;−1 to <i>z</i>&nbsp;=&nbsp;1 and then using Gauss's theorem to evaluate the result. A typical example is Kummer's theorem, named for <a href="Ernst_Kummer" title="Ernst Kummer">Ernst Kummer</a>:
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}(a,b;1+a-b;-1)={\frac {\Gamma (1+a-b)\Gamma (1+{\tfrac {1}{2}}a)}{\Gamma (1+a)\Gamma (1+{\tfrac {1}{2}}a-b)}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>a</mi>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}(a,b;1+a-b;-1)={\frac {\Gamma (1+a-b)\Gamma (1+{\tfrac {1}{2}}a)}{\Gamma (1+a)\Gamma (1+{\tfrac {1}{2}}a-b)}}}</annotation>
</semantics>
</math></span></span>
</p><p>which follows from Kummer's quadratic transformations
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{aligned}_{2}F_{1}(a,b;1+a-b;z)&amp;=(1-z)^{-a}\;_{2}F_{1}\left({\frac {a}{2}},{\frac {1+a}{2}}-b;1+a-b;-{\frac {4z}{(1-z)^{2}}}\right)\\&amp;=(1+z)^{-a}\,_{2}F_{1}\left({\frac {a}{2}},{\frac {a+1}{2}};1+a-b;{\frac {4z}{(1+z)^{2}}}\right)\end{aligned}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true">
<mtr>
<mtd>
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mi>z</mi>
<mo stretchy="false">)</mo>
</mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<msub>
<mspace width="thickmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>a</mi>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
</mrow>
<mn>2</mn>
</mfrac>
</mrow>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mo>−<!-- − --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>z</mi>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mi></mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
<msub>
<mspace width="thinmathspace"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mi>a</mi>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi>a</mi>
<mo>+</mo>
<mn>1</mn>
</mrow>
<mn>2</mn>
</mfrac>
</mrow>
<mo>;</mo>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>b</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mn>4</mn>
<mi>z</mi>
</mrow>
<mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>+</mo>
<mi>z</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
</mtd>
</mtr>
</mtable>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}_{2}F_{1}(a,b;1+a-b;z)&amp;=(1-z)^{-a}\;_{2}F_{1}\left({\frac {a}{2}},{\frac {1+a}{2}}-b;1+a-b;-{\frac {4z}{(1-z)^{2}}}\right)\\&amp;=(1+z)^{-a}\,_{2}F_{1}\left({\frac {a}{2}},{\frac {a+1}{2}};1+a-b;{\frac {4z}{(1+z)^{2}}}\right)\end{aligned}}}</annotation>
</semantics>
</math></span></span>
</p><p>and Gauss's theorem by putting <i>z</i>&nbsp;=&nbsp;−1 in the first identity. For generalization of Kummer's summation, see <a href="#CITEREFLavoieGrondinRathie1996">Lavoie, Grondin &amp; Rathie (1996)</a>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Values_at_z_=_1/2">Values at <i>z</i>&nbsp;=&nbsp;1/2</h3></div>
<p>Gauss's second summation theorem is
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle _{2}F_{1}\left(a,b;{\tfrac {1}{2}}\left(1+a+b\right);{\tfrac {1}{2}}\right)={\frac {\Gamma ({\tfrac {1}{2}})\Gamma ({\tfrac {1}{2}}\left(1+a+b\right))}{\Gamma ({\tfrac {1}{2}}\left(1+a)\right)\Gamma ({\tfrac {1}{2}}\left(1+b\right))}}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo>+</mo>
<mi>b</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>a</mi>
<mo stretchy="false">)</mo>
</mrow>
<mo>)</mo>
</mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>b</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle _{2}F_{1}\left(a,b;{\tfrac {1}{2}}\left(1+a+b\right);{\tfrac {1}{2}}\right)={\frac {\Gamma ({\tfrac {1}{2}})\Gamma ({\tfrac {1}{2}}\left(1+a+b\right))}{\Gamma ({\tfrac {1}{2}}\left(1+a)\right)\Gamma ({\tfrac {1}{2}}\left(1+b\right))}}.}</annotation>
</semantics>
</math></span></span>
</p><p>Bailey's theorem is
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle _{2}F_{1}\left(a,1-a;c;{\tfrac {1}{2}}\right)={\frac {\Gamma ({\tfrac {1}{2}}c)\Gamma ({\tfrac {1}{2}}\left(1+c\right))}{\Gamma ({\tfrac {1}{2}}\left(c+a\right))\Gamma ({\tfrac {1}{2}}\left(1+c-a\right))}}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<mi>c</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mi>c</mi>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>c</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mi>c</mi>
<mo>+</mo>
<mi>a</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">)</mo>
<mi mathvariant="normal">Γ<!-- Γ --></mi>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mrow>
<mo>(</mo>
<mrow>
<mn>1</mn>
<mo>+</mo>
<mi>c</mi>
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
<mo>)</mo>
</mrow>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mrow>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle _{2}F_{1}\left(a,1-a;c;{\tfrac {1}{2}}\right)={\frac {\Gamma ({\tfrac {1}{2}}c)\Gamma ({\tfrac {1}{2}}\left(1+c\right))}{\Gamma ({\tfrac {1}{2}}\left(c+a\right))\Gamma ({\tfrac {1}{2}}\left(1+c-a\right))}}.}</annotation>
</semantics>
</math></span></span>
</p><p>For generalizations of Gauss's second summation theorem and Bailey's summation theorem, see <a href="#CITEREFLavoieGrondinRathie1996">Lavoie, Grondin &amp; Rathie (1996)</a>.
</p>
<div class="mw-heading mw-heading3"><h3 id="Other_points">Other points</h3></div>
<p>There are many other formulas giving the hypergeometric function as an algebraic number at special rational values of the parameters, some of which are listed in <a href="#CITEREFGesselStanton1982">Gessel &amp; Stanton (1982)</a> and <a href="#CITEREFKoepf1995">Koepf (1995)</a>. Some typical examples are given by
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {}_{2}F_{1}\left(a,-a;{\tfrac {1}{2}};{\tfrac {x^{2}}{4(x-1)}}\right)={\frac {(1-x)^{a}+(1-x)^{-a}}{2}},}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mrow>
<mn>4</mn>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mstyle>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>x</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>a</mi>
</mrow>
</msup>
<mo>+</mo>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>x</mi>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mi>a</mi>
</mrow>
</msup>
</mrow>
<mn>2</mn>
</mfrac>
</mrow>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle {}_{2}F_{1}\left(a,-a;{\tfrac {1}{2}};{\tfrac {x^{2}}{4(x-1)}}\right)={\frac {(1-x)^{a}+(1-x)^{-a}}{2}},}</annotation>
</semantics>
</math></span></span>
</p><p>which can be restated as
</p><p><span class="mwe-math-element mwe-math-element-block"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle T_{a}(\cos x)={}_{2}F_{1}\left(a,-a;{\tfrac {1}{2}};{\tfrac {1}{2}}(1-\cos x)\right)=\cos(ax)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>T</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>a</mi>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>cos</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<msub>
<mrow class="MJX-TeXAtom-ORD">

</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<msub>
<mi>F</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow>
<mo>(</mo>
<mrow>
<mi>a</mi>
<mo>,</mo>
<mo>−<!-- − --></mo>
<mi>a</mi>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo>;</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mn>1</mn>
<mn>2</mn>
</mfrac>
</mstyle>
</mrow>
<mo stretchy="false">(</mo>
<mn>1</mn>
<mo>−<!-- − --></mo>
<mi>cos</mi>
<mo>⁡<!-- ⁡ --></mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mi>cos</mi>
<mo>⁡<!-- ⁡ --></mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle T_{a}(\cos x)={}_{2}F_{1}\left(a,-a;{\tfrac {1}{2}};{\tfrac {1}{2}}(1-\cos x)\right)=\cos(ax)}</annotation>
</semantics>
</math></span></span>
</p><p>whenever −π &lt; <i>x</i> &lt; π and <i>T</i> is the (generalized) <a href="Chebyshev_polynomial" class="mw-redirect" title="Chebyshev polynomial">Chebyshev polynomial</a>.
</p>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Appell_series" title="Appell series">Appell series</a></li>
<li><a href="Basic_hypergeometric_series" title="Basic hypergeometric series">Basic hypergeometric series</a></li>
<li><a href="Bilateral_hypergeometric_series" title="Bilateral hypergeometric series">Bilateral hypergeometric series</a></li>
<li><a href="Elliptic_hypergeometric_series" title="Elliptic hypergeometric series">Elliptic hypergeometric series</a></li>
<li><a href="General_hypergeometric_function" title="General hypergeometric function">General hypergeometric function</a></li>
<li><a href="Generalized_hypergeometric_series" class="mw-redirect" title="Generalized hypergeometric series">Generalized hypergeometric series</a></li>
<li><a href="Hypergeometric_distribution" title="Hypergeometric distribution">Hypergeometric distribution</a></li>
<li><a href="Lauricella_hypergeometric_series" title="Lauricella hypergeometric series">Lauricella hypergeometric series</a></li>
<li><a href="Modular_hypergeometric_series" class="mw-redirect" title="Modular hypergeometric series">Modular hypergeometric series</a></li>
<li><a href="Riemann's_differential_equation" title="Riemann's differential equation">Riemann's differential equation</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
<style data-mw-deduplicate="TemplateStyles:r1239543626">
/* start https://en.wikipedia.org/ */


.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}


/* end https://en.wikipedia.org/ */
</style><div class="reflist">
<div class="mw-references-wrap"><ol class="references">
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
/* start https://en.wikipedia.org/ */


.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}


/* end https://en.wikipedia.org/ */
</style><cite id="CITEREFMorita1996" class="citation journal cs1">Morita, Tohru (1996). "Use of the Gauss contiguous relations in computing the hypergeometric functions F(n+1/2,n+1/2;m;z)". <i>Interd. Inf. Sci</i>. <b>2</b> (1): <span class="nowrap">63–</span>74. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.4036%2Fiis.1996.63">10.4036/iis.1996.63</a>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=1398101">1398101</a>.</cite></span>
</li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><a href="#CITEREFInce1944">Ince 1944</a>, pp.&nbsp;393–393</span>
</li>
<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><cite id="CITEREFRakhaRathieChopra2011" class="citation journal cs1">Rakha, Medhat A.; Rathie, Arjun K.; Chopra, Purnima (2011). "On some new contiguous relations for the Gauss hypergeometric function with applications". <i>Comput. Math. Appl</i>. <b>61</b> (3): <span class="nowrap">620–</span>629. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.camwa.2010.12.008">10.1016/j.camwa.2010.12.008</a>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=2764057">2764057</a>.</cite></span>
</li>
</ol></div></div>
<div class="mw-references-wrap"><ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">This convention is common in hypergeometric function theory, but it is the opposite convention to the one used in <a href="Falling_and_rising_factorials" title="Falling and rising factorials">Falling and rising factorials</a>.</span>
</li>
</ol></div><div class="reflist reflist-lower-alpha">
</div>
<ul><li><cite id="CITEREFAndrewsAskeyRoy1999" class="citation book cs1"><a href="George_Andrews_(mathematician)" title="George Andrews (mathematician)">Andrews, George E.</a>; Askey, Richard &amp; Roy, Ranjan (1999). <i>Special functions</i>. Encyclopedia of Mathematics and its Applications. Vol.&nbsp;71. Cambridge University Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-521-62321-6</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=1688958">1688958</a>.</cite></li>
<li><cite id="CITEREFBailey1935" class="citation book cs1">Bailey, W.N. (1935). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170624164738/http://plouffe.fr/simon/math/Bailey%20W.N.%20Generalized%20Hypergeometric%20Series%20(1964)(L)(T)(59s).pdf"><i>Generalized Hypergeometric Series</i></a> <span class="cs1-format">(PDF)</span>. Cambridge University Press. Archived from <a rel="nofollow" class="external text" href="http://plouffe.fr/simon/math/Bailey%20W.N.%20Generalized%20Hypergeometric%20Series%20%281964%29%28L%29%28T%29%2859s%29.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2017-06-24<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-07-23</span></span>.</cite></li>
<li><a href="Frits_Beukers" title="Frits Beukers">Beukers, Frits</a> (2002), <i><a rel="nofollow" class="external text" href="https://webspace.science.uu.nl/~beuke106/MRIcourse93.ps">Gauss' hypergeometric function</a></i>. (lecture notes reviewing basics, as well as triangle maps and monodromy)</li>
<li><cite id="CITEREFOlde_Daalhuis2010" class="citation cs2">Olde Daalhuis, Adri B. (2010), <a rel="nofollow" class="external text" href="http://dlmf.nist.gov/15">"Hypergeometric function"</a>, in <a href="Frank_W._J._Olver" title="Frank W. J. Olver">Olver, Frank W. J.</a>; Lozier, Daniel M.; Boisvert, Ronald F.; Clark, Charles W. (eds.), <i><a href="Digital_Library_of_Mathematical_Functions" title="Digital Library of Mathematical Functions">NIST Handbook of Mathematical Functions</a></i>, Cambridge University Press, <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-521-19225-5</bdi>, <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=2723248">2723248</a></cite>.</li>
<li><cite id="CITEREFErdélyiMagnusOberhettingerTricomi1953" class="citation book cs1"><a href="Arthur_Erd%C3%A9lyi" title="Arthur Erdélyi">Erdélyi, Arthur</a>; <a href="Wilhelm_Magnus" title="Wilhelm Magnus">Magnus, Wilhelm</a>; Oberhettinger, Fritz &amp; Tricomi, Francesco G. (1953). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110811153220/http://apps.nrbook.com/bateman/Vol1.pdf"><i>Higher transcendental functions</i></a> <span class="cs1-format">(PDF)</span>. Vol.&nbsp;I. New York – Toronto – London: McGraw–Hill Book Company, Inc. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-89874-206-0</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=0058756">0058756</a>. Archived from <a rel="nofollow" class="external text" href="http://apps.nrbook.com/bateman/Vol1.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2011-08-11<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-07-30</span></span>.</cite> <span class="cs1-hidden-error citation-comment"><code class="cs1-code">{{cite book}}</code>: </span><span class="cs1-hidden-error citation-comment">ISBN / Date incompatibility (help)</span></li>
<li><a href="George_Gasper" title="George Gasper">Gasper, George</a> &amp; <a href="Mizan_Rahman" title="Mizan Rahman">Rahman, Mizan</a> (2004). Basic Hypergeometric Series, 2nd Edition, Encyclopedia of Mathematics and Its Applications, 96, Cambridge University Press, Cambridge. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>0-521-83357-4</bdi>.</li>
<li><cite id="CITEREFGauss1813" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="Carl_Friedrich_Gauss" title="Carl Friedrich Gauss">Gauss, Carl Friedrich</a> (1813). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=uDMAAAAAQAAJ">"Disquisitiones generales circa seriem infinitam &nbsp; <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1+{\tfrac {\alpha \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}~x~x+{\mbox{etc.}}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>α<!-- α --></mi>
<mi>β<!-- β --></mi>
</mrow>
<mrow>
<mn>1</mn>
<mo>⋅<!-- ⋅ --></mo>
<mi>γ<!-- γ --></mi>
</mrow>
</mfrac>
</mstyle>
</mrow>
<mtext>&nbsp;</mtext>
<mi>x</mi>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>α<!-- α --></mi>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mi>β<!-- β --></mi>
<mo stretchy="false">(</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>⋅<!-- ⋅ --></mo>
<mn>2</mn>
<mo>⋅<!-- ⋅ --></mo>
<mi>γ<!-- γ --></mi>
<mo stretchy="false">(</mo>
<mi>γ<!-- γ --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mstyle>
</mrow>
<mtext>&nbsp;</mtext>
<mi>x</mi>
<mtext>&nbsp;</mtext>
<mi>x</mi>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mtext>etc.</mtext>
</mstyle>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle 1+{\tfrac {\alpha \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}~x~x+{\mbox{etc.}}}</annotation>
</semantics>
</math></span><img src="./5351a876f44e876445e2481dcdbea2ecd91fec97.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:33.622ex; height:4.843ex;" alt="{\displaystyle 1+{\tfrac {\alpha \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}~x~x+{\mbox{etc.}}}" loading="lazy"></span>"</a>. <i>Commentationes Societatis Regiae Scientarum Gottingensis Recentiores</i> (in Latin). <b>2</b>. Göttingen.</cite></li>
<li><cite id="CITEREFGelfandGindikinGraev2003" class="citation book cs1"><a href="Israel_Gelfand" title="Israel Gelfand">Gelfand, I. M.</a>; <a href="Simon_Gindikin" title="Simon Gindikin">Gindikin, S.G.</a> &amp; <a href="Mark_Iosifovich_Graev" title="Mark Iosifovich Graev">Graev, M.I.</a> (2003) [2000]. <a rel="nofollow" class="external text" href="https://books.google.com/books?isbn=0821829327"><i>Selected topics in integral geometry</i></a>. Translations of Mathematical Monographs. Vol.&nbsp;220. Providence, R.I.: <a href="American_Mathematical_Society" title="American Mathematical Society">American Mathematical Society</a>. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-8218-2932-5</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=2000133">2000133</a>.</cite></li>
<li><cite id="CITEREFGesselStanton1982" class="citation journal cs1"><a href="Ira_Gessel" title="Ira Gessel">Gessel, Ira</a> &amp; Stanton, Dennis (1982). "Strange evaluations of hypergeometric series". <i>SIAM Journal on Mathematical Analysis</i>. <b>13</b> (2): <span class="nowrap">295–</span>308. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1137%2F0513021">10.1137/0513021</a>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a>&nbsp;<a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0036-1410">0036-1410</a>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=0647127">0647127</a>.</cite></li>
<li><cite id="CITEREFGoursat1881" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="%C3%89douard_Goursat" title="Édouard Goursat">Goursat, Édouard</a> (1881). <a rel="nofollow" class="external text" href="http://www.numdam.org/item?id=ASENS_1881_2_10__S3_0">"Sur l'équation différentielle linéaire, qui admet pour intégrale la série hypergéométrique"</a>. <i>Annales Scientifiques de l'École Normale Supérieure</i> (in French). <b>10</b>: <span class="nowrap">3–</span>142. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.24033%2Fasens.207">10.24033/asens.207</a></span><span class="reference-accessdate">. Retrieved <span class="nowrap">2008-10-16</span></span>.</cite></li>
<li><cite id="CITEREFHeckmanSchlichtkrull1994" class="citation book cs1">Heckman, Gerrit &amp; Schlichtkrull, Henrik (1994). <i>Harmonic Analysis and Special Functions on Symmetric Spaces</i>. San Diego: Academic Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>0-12-336170-2</bdi>.</cite> (part 1 treats hypergeometric functions on Lie groups)</li>
<li><cite id="CITEREFHille1976" class="citation book cs1"><a href="Einar_Hille" title="Einar Hille">Hille, Einar</a> (1976). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/ordinarydifferen00hill_0"><i>Ordinary differential equations in the complex domain</i></a></span>. Dover. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>0-486-69620-0</bdi>.</cite></li>
<li><cite id="CITEREFInce1944" class="citation book cs1"><a href="E._L._Ince" class="mw-redirect" title="E. L. Ince">Ince, E. L.</a> (1944). <a rel="nofollow" class="external text" href="https://archive.org/details/in.ernet.dli.2015.476224"><i>Ordinary Differential Equations</i></a>. Dover Publications.</cite></li>
<li><cite id="CITEREFKlein1981" class="citation book cs1 cs1-prop-foreign-lang-source"><a href="Felix_Klein" title="Felix Klein">Klein, Felix</a> (1981). <a rel="nofollow" class="external text" href="http://resolver.sub.uni-goettingen.de/purl?PPN375394591"><i>Vorlesungen über die hypergeometrische Funktion</i></a>. Grundlehren der Mathematischen Wissenschaften (in German). Vol.&nbsp;39. Berlin, New York: Springer-Verlag. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-3-540-10455-1</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=0668700">0668700</a>.</cite></li>
<li><cite id="CITEREFKoepf1995" class="citation journal cs1">Koepf, Wolfram (1995). <a rel="nofollow" class="external text" href="https://doi.org/10.1006%2Fjsco.1995.1056">"Algorithms for m-fold hypergeometric summation"</a>. <i>Journal of Symbolic Computation</i>. <b>20</b> (4): <span class="nowrap">399–</span>417. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1006%2Fjsco.1995.1056">10.1006/jsco.1995.1056</a></span>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a>&nbsp;<a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0747-7171">0747-7171</a>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=1384455">1384455</a>.</cite></li>
<li><cite id="CITEREFKummer1836" class="citation journal cs1 cs1-prop-foreign-lang-source">Kummer, Ernst Eduard (1836). <a rel="nofollow" class="external text" href="http://resolver.sub.uni-goettingen.de/purl?GDZPPN00214056X">"Über die hypergeometrische Reihe&nbsp;<span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1+{\tfrac {\alpha \cdot \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}x^{2}+{\tfrac {\alpha (\alpha +1)(\alpha +2)\beta (\beta +1)(\beta +2)}{1\cdot 2\cdot 3\cdot \gamma (\gamma +1)(\gamma +2)}}x^{3}+\cdots }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mn>1</mn>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>α<!-- α --></mi>
<mo>⋅<!-- ⋅ --></mo>
<mi>β<!-- β --></mi>
</mrow>
<mrow>
<mn>1</mn>
<mo>⋅<!-- ⋅ --></mo>
<mi>γ<!-- γ --></mi>
</mrow>
</mfrac>
</mstyle>
</mrow>
<mtext>&nbsp;</mtext>
<mi>x</mi>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>α<!-- α --></mi>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mi>β<!-- β --></mi>
<mo stretchy="false">(</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>⋅<!-- ⋅ --></mo>
<mn>2</mn>
<mo>⋅<!-- ⋅ --></mo>
<mi>γ<!-- γ --></mi>
<mo stretchy="false">(</mo>
<mi>γ<!-- γ --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mstyle>
</mrow>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>+</mo>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="false" scriptlevel="0">
<mfrac>
<mrow>
<mi>α<!-- α --></mi>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>α<!-- α --></mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
<mi>β<!-- β --></mi>
<mo stretchy="false">(</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>β<!-- β --></mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>⋅<!-- ⋅ --></mo>
<mn>2</mn>
<mo>⋅<!-- ⋅ --></mo>
<mn>3</mn>
<mo>⋅<!-- ⋅ --></mo>
<mi>γ<!-- γ --></mi>
<mo stretchy="false">(</mo>
<mi>γ<!-- γ --></mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>γ<!-- γ --></mi>
<mo>+</mo>
<mn>2</mn>
<mo stretchy="false">)</mo>
</mrow>
</mfrac>
</mstyle>
</mrow>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>+</mo>
<mo>⋯<!-- ⋯ --></mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle 1+{\tfrac {\alpha \cdot \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}x^{2}+{\tfrac {\alpha (\alpha +1)(\alpha +2)\beta (\beta +1)(\beta +2)}{1\cdot 2\cdot 3\cdot \gamma (\gamma +1)(\gamma +2)}}x^{3}+\cdots }</annotation>
</semantics>
</math></span><img src="./a24bc1c17525b5489ed65732c5ccc99366ec340e.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:57.133ex; height:4.843ex;" alt="{\displaystyle 1+{\tfrac {\alpha \cdot \beta }{1\cdot \gamma }}~x+{\tfrac {\alpha (\alpha +1)\beta (\beta +1)}{1\cdot 2\cdot \gamma (\gamma +1)}}x^{2}+{\tfrac {\alpha (\alpha +1)(\alpha +2)\beta (\beta +1)(\beta +2)}{1\cdot 2\cdot 3\cdot \gamma (\gamma +1)(\gamma +2)}}x^{3}+\cdots }" loading="lazy"></span>"</a>. <i><a href="Journal_f%C3%BCr_die_reine_und_angewandte_Mathematik" class="mw-redirect" title="Journal für die reine und angewandte Mathematik">Journal für die reine und angewandte Mathematik</a></i> (in German). <b>15</b>: <span class="nowrap">39–</span>83, <span class="nowrap">127–</span>172. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a>&nbsp;<a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0075-4102">0075-4102</a>.</cite></li>
<li><cite id="CITEREFLavoieGrondinRathie1996" class="citation journal cs1">Lavoie, J. L.; Grondin, F.; Rathie, A.K. (1996). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0377-0427%2895%2900279-0">"Generalizations of Whipple's theorem on the sum of a <sub>3</sub>F<sub>2</sub>"</a>. <i>J. Comput. Appl. Math</i>. <b>72</b> (2): <span class="nowrap">293–</span>300. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0377-0427%2895%2900279-0">10.1016/0377-0427(95)00279-0</a></span>.</cite></li>
<li><cite id="CITEREFPressTeukolskyVetterlingFlannery2007" class="citation book cs1">Press, W.H.; Teukolsky, S.A.; Vetterling, W.T. &amp; Flannery, B.P. (2007). <a rel="nofollow" class="external text" href="http://apps.nrbook.com/empanel/index.html#pg=318">"Section 6.13. Hypergeometric Functions"</a>. <i>Numerical Recipes: The Art of Scientific Computing</i> (3rd&nbsp;ed.). New York: Cambridge University Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-521-88068-8</bdi>.</cite></li>
<li><cite id="CITEREFRakhaRathie2011" class="citation journal cs1">Rakha, M.A.; Rathie, Arjun K. (2011). <a rel="nofollow" class="external text" href="https://doi.org/10.4134%2FBKMS.2011.48.1.151">"Extensions of Euler's type-II transformation and Saalschutz's theorem"</a>. <i>Bull. Korean Math. Soc</i>. <b>48</b> (1): <span class="nowrap">151–</span>156. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.4134%2FBKMS.2011.48.1.151">10.4134/BKMS.2011.48.1.151</a></span>.</cite></li>
<li><cite id="CITEREFRathieParis2007" class="citation journal cs1">Rathie, Arjun K.; Paris, R.B. (2007). "An extension of the Euler's-type transformation for the 3F2 series". <i>Far East J. Math. Sci</i>. <b>27</b> (1): <span class="nowrap">43–</span>48.</cite></li>
<li><cite id="CITEREFRiemann1857" class="citation journal cs1 cs1-prop-foreign-lang-source"><a href="Bernhard_Riemann" title="Bernhard Riemann">Riemann, Bernhard</a> (1857). <a rel="nofollow" class="external text" href="http://gdz.sub.uni-goettingen.de/dms/load/img/?PPN=GDZPPN002018691">"Beiträge zur Theorie der durch die Gauss'sche Reihe <i>F(α, β, γ, x)</i> darstellbaren Functionen"</a>. <i>Abhandlungen der Mathematischen Classe der Königlichen Gesellschaft der Wissenschaften zu Göttingen</i> (in German). <b>7</b>. Göttingen: Verlag der Dieterichschen Buchhandlung: <span class="nowrap">3–</span>22.</cite> (a reprint of this paper can be found in <cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.emis.de/classics/Riemann/PFunct.pdf">"All publications of Riemann"</a> <span class="cs1-format">(PDF)</span>.</cite>)</li>
<li><cite id="CITEREFSlater1960" class="citation book cs1"><a href="Lucy_Joan_Slater" title="Lucy Joan Slater">Slater, Lucy Joan</a> (1960). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/confluenthyperge0000slat"><i>Confluent hypergeometric functions</i></a></span>. Cambridge, UK: Cambridge University Press. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=0107026">0107026</a>.</cite></li>
<li><cite id="CITEREFSlater1966" class="citation book cs1"><a href="Lucy_Joan_Slater" title="Lucy Joan Slater">Slater, Lucy Joan</a> (1966). <i>Generalized hypergeometric functions</i>. Cambridge, UK: Cambridge University Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>0-521-06483-X</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=0201688">0201688</a>.</cite> (there is a 2008 paperback with <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-521-09061-2</bdi>)</li>
<li><cite id="CITEREFVidunas2005" class="citation journal cs1">Vidunas, Raimundas (2005). "Transformations of some Gauss hypergeometric functions". <i>Journal of Symbolic Computation</i>. <b>178</b> (<span class="nowrap">1–</span>2): <span class="nowrap">473–</span>487. <a href="ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/math/0310436">math/0310436</a></span>. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2005JCoAM.178..473V">2005JCoAM.178..473V</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.cam.2004.09.053">10.1016/j.cam.2004.09.053</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a>&nbsp;<a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:119596800">119596800</a>.</cite></li>
<li><cite id="CITEREFWall1948" class="citation book cs1">Wall, H.S. (1948). <i>Analytic Theory of Continued Fractions</i>. D. Van Nostrand Company, Inc.</cite></li>
<li><cite id="CITEREFWhittakerWatson1927" class="citation book cs1"><a href="E._T._Whittaker" title="E. T. Whittaker">Whittaker, E.T.</a> &amp; <a href="G._N._Watson" title="G. N. Watson">Watson, G.N.</a> (1927). <i><a href="A_Course_of_Modern_Analysis" title="A Course of Modern Analysis">A Course of Modern Analysis</a></i>. Cambridge, UK: Cambridge University Press.</cite></li>
<li><cite id="CITEREFYoshida1997" class="citation book cs1">Yoshida, Masaaki (1997). <i>Hypergeometric Functions, My Love: Modular Interpretations of Configuration Spaces</i>. Braunschweig – Wiesbaden: Friedr. Vieweg &amp; Sohn. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>3-528-06925-2</bdi>. <a href="MR_(identifier)" class="mw-redirect" title="MR (identifier)">MR</a>&nbsp;<a rel="nofollow" class="external text" href="https://mathscinet.ams.org/mathscinet-getitem?mr=1453580">1453580</a>.</cite></li></ul>
<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://www.encyclopediaofmath.org/index.php?title=Hypergeometric_function">"Hypergeometric function"</a>, <i><a href="Encyclopedia_of_Mathematics" title="Encyclopedia of Mathematics">Encyclopedia of Mathematics</a></i>, <a href="European_Mathematical_Society" title="European Mathematical Society">EMS Press</a>, 2001 [1994]</cite></li>
<li>John Pearson, <a rel="nofollow" class="external text" href="http://people.maths.ox.ac.uk/porterm/research/pearson_final.pdf">Computation of Hypergeometric Functions</a> (<a href="University_of_Oxford" title="University of Oxford">University of Oxford</a>, MSc Thesis)</li>
<li>Marko Petkovsek, Herbert Wilf and Doron Zeilberger, <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060129095451/http://www.cis.upenn.edu/~wilf/AeqB.html">The book "A = B"</a> (freely downloadable)</li>
<li><span class="citation mathworld" id="Reference-Mathworld-Hypergeometric_Function"><cite id="CITEREFWeisstein" class="citation web cs1"><a href="Eric_W._Weisstein" title="Eric W. Weisstein">Weisstein, Eric W.</a> <a rel="nofollow" class="external text" href="https://mathworld.wolfram.com/HypergeometricFunction.html">"Hypergeometric Function"</a>. <i><a href="MathWorld" title="MathWorld">MathWorld</a></i>.</cite></span></li></ul>
<div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">
/* start https://en.wikipedia.org/ */


.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}


/* end https://en.wikipedia.org/ */
</style><style data-mw-deduplicate="TemplateStyles:r1236075235">
/* start https://en.wikipedia.org/ */


.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}


/* end https://en.wikipedia.org/ */
</style></div><div role="navigation" class="navbox" aria-labelledby="Sequences_and_series332" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><style data-mw-deduplicate="TemplateStyles:r1239400231">
/* start https://en.wikipedia.org/ */


.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}


/* end https://en.wikipedia.org/ */
</style><div id="Sequences_and_series332" style="font-size:114%;margin:0 4em"><a href="Sequence" title="Sequence">Sequences</a> and <a href="Series_(mathematics)" title="Series (mathematics)">series</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Integer_sequence" title="Integer sequence">Integer sequences</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Basic</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Arithmetic_progression" title="Arithmetic progression">Arithmetic progression</a></li>
<li><a href="Geometric_progression" title="Geometric progression">Geometric progression</a></li>
<li><a href="Harmonic_progression_(mathematics)" title="Harmonic progression (mathematics)">Harmonic progression</a></li>
<li><a href="Square_number" title="Square number">Square number</a></li>
<li><a href="Cube_(algebra)" title="Cube (algebra)">Cubic number</a></li>
<li><a href="Factorial" title="Factorial">Factorial</a></li>
<li><a href="Power_of_two" title="Power of two">Powers of two</a></li>
<li><a href="Power_of_three" title="Power of three">Powers of three</a></li>
<li><a href="Power_of_10" title="Power of 10">Powers of 10</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Advanced <span class="nobold">(<a href="List_of_OEIS_sequences" class="mw-redirect" title="List of OEIS sequences">list</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Complete_sequence" title="Complete sequence">Complete sequence</a></li>
<li><a href="Fibonacci_sequence" title="Fibonacci sequence">Fibonacci sequence</a></li>
<li><a href="Figurate_number" title="Figurate number">Figurate number</a></li>
<li><a href="Heptagonal_number" title="Heptagonal number">Heptagonal number</a></li>
<li><a href="Hexagonal_number" title="Hexagonal number">Hexagonal number</a></li>
<li><a href="Lucas_number" title="Lucas number">Lucas number</a></li>
<li><a href="Pell_number" title="Pell number">Pell number</a></li>
<li><a href="Pentagonal_number" title="Pentagonal number">Pentagonal number</a></li>
<li><a href="Polygonal_number" title="Polygonal number">Polygonal number</a></li>
<li><a href="Triangular_number" title="Triangular number">Triangular number</a>
<ul><li><a href="Triangular_array" title="Triangular array">array</a></li></ul></li></ul>
</div></td></tr></tbody></table><div></div></td><td class="noviewer navbox-image" rowspan="6" style="width:1px;padding:0 0 0 2px"><div><span typeof="mw:File"><a href="Fibonacci_sequence" title="Fibonacci sequence"></a></span></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Properties of sequences</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Cauchy_sequence" title="Cauchy sequence">Cauchy sequence</a></li>
<li><a href="Monotonic_function" title="Monotonic function">Monotonic function</a></li>
<li><a href="Periodic_sequence" title="Periodic sequence">Periodic sequence</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Properties of series</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Series</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Alternating_series" title="Alternating series">Alternating</a></li>
<li><a href="Convergent_series" title="Convergent series">Convergent</a></li>
<li><a href="Divergent_series" title="Divergent series">Divergent</a></li>
<li><a href="Telescoping_series" title="Telescoping series">Telescoping</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Convergence</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Absolute_convergence" title="Absolute convergence">Absolute</a></li>
<li><a href="Conditional_convergence" title="Conditional convergence">Conditional</a></li>
<li><a href="Uniform_convergence" title="Uniform convergence">Uniform</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Explicit series</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Convergent</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="1/2_%E2%88%92_1/4_%2B_1/8_%E2%88%92_1/16_%2B_%E2%8B%AF" title="1/2 − 1/4 + 1/8 − 1/16 + ⋯">1/2 − 1/4 + 1/8 − 1/16 + ⋯</a></li>
<li><a href="1/2_%2B_1/4_%2B_1/8_%2B_1/16_%2B_%E2%8B%AF" title="1/2 + 1/4 + 1/8 + 1/16 + ⋯">1/2 + 1/4 + 1/8 + 1/16 + ⋯</a></li>
<li><a href="1/4_%2B_1/16_%2B_1/64_%2B_1/256_%2B_%E2%8B%AF" title="1/4 + 1/16 + 1/64 + 1/256 + ⋯">1/4 + 1/16 + 1/64 + 1/256 + ⋯</a></li>
<li><a href="Riemann_zeta_function" title="Riemann zeta function">1 + 1/2<sup><i>s</i></sup> + 1/3<sup><i>s</i></sup> + ... (Riemann zeta function)</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;text-align:left">Divergent</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="1_%2B_1_%2B_1_%2B_1_%2B_%E2%8B%AF" title="1 + 1 + 1 + 1 + ⋯">1 + 1 + 1 + 1 + ⋯</a></li>
<li><a href="Grandi's_series" title="Grandi's series">1 − 1 + 1 − 1 + ⋯ (Grandi's series)</a></li>
<li><a href="1_%2B_2_%2B_3_%2B_4_%2B_%E2%8B%AF" title="1 + 2 + 3 + 4 + ⋯">1 + 2 + 3 + 4 + ⋯</a></li>
<li><a href="1_%E2%88%92_2_%2B_3_%E2%88%92_4_%2B_%E2%8B%AF" title="1 − 2 + 3 − 4 + ⋯">1 − 2 + 3 − 4 + ⋯</a></li>
<li><a href="1_%2B_2_%2B_4_%2B_8_%2B_%E2%8B%AF" title="1 + 2 + 4 + 8 + ⋯">1 + 2 + 4 + 8 + ⋯</a></li>
<li><a href="1_%E2%88%92_2_%2B_4_%E2%88%92_8_%2B_%E2%8B%AF" title="1 − 2 + 4 − 8 + ⋯">1 − 2 + 4 − 8 + ⋯</a></li>
<li><a href="Infinite_arithmetic_series" class="mw-redirect" title="Infinite arithmetic series">Infinite arithmetic series</a></li>
<li><a href="1_%E2%88%92_1_%2B_2_%E2%88%92_6_%2B_24_%E2%88%92_120_%2B_%E2%8B%AF" title="1 − 1 + 2 − 6 + 24 − 120 + ⋯">1 − 1 + 2 − 6 + 24 − 120 + ⋯ (alternating factorials)</a></li>
<li><a href="Harmonic_series_(mathematics)" title="Harmonic series (mathematics)">1 + 1/2 + 1/3 + 1/4 + ⋯ (harmonic series)</a></li>
<li><a href="Divergence_of_the_sum_of_the_reciprocals_of_the_primes" title="Divergence of the sum of the reciprocals of the primes">1/2 + 1/3 + 1/5 + 1/7 + 1/11 + ⋯ (inverses of primes)</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Kinds of series</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Taylor_series" title="Taylor series">Taylor series</a></li>
<li><a href="Power_series" title="Power series">Power series</a></li>
<li><a href="Formal_power_series" title="Formal power series">Formal power series</a></li>
<li><a href="Laurent_series" title="Laurent series">Laurent series</a></li>
<li><a href="Puiseux_series" title="Puiseux series">Puiseux series</a></li>
<li><a href="Dirichlet_series" title="Dirichlet series">Dirichlet series</a></li>
<li><a href="Trigonometric_series" title="Trigonometric series">Trigonometric series</a></li>
<li><a href="Fourier_series" title="Fourier series">Fourier series</a></li>
<li><a href="Generating_series" class="mw-redirect" title="Generating series">Generating series</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">
<ul><li><a href="Generalized_hypergeometric_series" class="mw-redirect" title="Generalized hypergeometric series">Generalized hypergeometric series</a></li>
<li><a href="Hypergeometric_function_of_a_matrix_argument" title="Hypergeometric function of a matrix argument">Hypergeometric function of a matrix argument</a></li>
<li><a href="Lauricella_hypergeometric_series" title="Lauricella hypergeometric series">Lauricella hypergeometric series</a></li>
<li><a href="Modular_hypergeometric_series" class="mw-redirect" title="Modular hypergeometric series">Modular hypergeometric series</a></li>
<li><a href="Riemann's_differential_equation" title="Riemann's differential equation">Riemann's differential equation</a></li>
<li><a href="Theta_hypergeometric_series" class="mw-redirect" title="Theta hypergeometric series">Theta hypergeometric series</a></li></ul>
</div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="3"><div>
<ul><li><span class="noviewer" typeof="mw:File"><span title="Category"></span></span> Category</li></ul>
</div></td></tr></tbody></table></div></div><!--htdig_noindex--><div><div class="zim-footer">
This article is issued from <a class="external text" title="Last edited on 2025-07-29" href="https://en.wikipedia.org/wiki/?title=Hypergeometric_function&amp;oldid=1303082072">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.
</div>
</div><!--/htdig_noindex--></div>
</div>
</main>
</div>
</div>
</div>

</body></html>