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>Set-builder notation</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="canonical" href="https://en.wikipedia.org/wiki/Set-builder_notation"> <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/ext.pygments.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-Set-builder_notation rootpage-Set-builder_notation 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">Set-builder notation</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">
<p class="mw-empty-elt">
</p>
<style data-mw-deduplicate="TemplateStyles:r1224211176">
/* start https://en.wikipedia.org/ */


.mw-parser-output .quotebox{background-color:#F9F9F9;border:1px solid #aaa;box-sizing:border-box;padding:10px;font-size:88%;max-width:100%}.mw-parser-output .quotebox.floatleft{margin:.5em 1.4em .8em 0}.mw-parser-output .quotebox.floatright{margin:.5em 0 .8em 1.4em}.mw-parser-output .quotebox.centered{overflow:hidden;position:relative;margin:.5em auto .8em auto}.mw-parser-output .quotebox.floatleft span,.mw-parser-output .quotebox.floatright span{font-style:inherit}.mw-parser-output .quotebox>blockquote{margin:0;padding:0;border-left:0;font-family:inherit;font-size:inherit}.mw-parser-output .quotebox-title{text-align:center;font-size:110%;font-weight:bold}.mw-parser-output .quotebox-quote>:first-child{margin-top:0}.mw-parser-output .quotebox-quote:last-child>:last-child{margin-bottom:0}.mw-parser-output .quotebox-quote.quoted:before{font-family:"Times New Roman",serif;font-weight:bold;font-size:large;color:gray;content:" “ ";vertical-align:-45%;line-height:0}.mw-parser-output .quotebox-quote.quoted:after{font-family:"Times New Roman",serif;font-weight:bold;font-size:large;color:gray;content:" ” ";line-height:0}.mw-parser-output .quotebox .left-aligned{text-align:left}.mw-parser-output .quotebox .right-aligned{text-align:right}.mw-parser-output .quotebox .center-aligned{text-align:center}.mw-parser-output .quotebox .quote-title,.mw-parser-output .quotebox .quotebox-quote{display:block}.mw-parser-output .quotebox cite{display:block;font-style:normal}@media screen and (max-width:640px){.mw-parser-output .quotebox{width:100%!important;margin:0 0 .8em!important;float:none!important}}


/* end https://en.wikipedia.org/ */
</style><div class="quotebox pullquote floatright" style=";">
<blockquote class="quotebox-quote left-aligned" style="">
<p><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 \{n\mid \exists k\in \mathbb {Z} ,n=2k\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>n</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>k</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo>,</mo>
<mi>n</mi>
<mo>=</mo>
<mn>2</mn>
<mi>k</mi>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{n\mid \exists k\in \mathbb {Z} ,n=2k\}}</annotation>
</semantics>
</math></span><img src="./3d08d5bbe9574a241428e503b8733c3d7366e413.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:20.452ex; height:2.843ex;" alt="{\displaystyle \{n\mid \exists k\in \mathbb {Z} ,n=2k\}}" loading="lazy"></span>
</p>
</blockquote>
<div style="padding-bottom: 0; padding-top: 0.5em"><cite class="left-aligned" style="">The set of all <a href="Even_integer" class="mw-redirect" title="Even integer">even integers</a>, <br> expressed in set-builder notation.</cite></div>
</div>
<p>In <a href="Mathematics" title="Mathematics">mathematics</a> and more specifically in <a href="Set_theory" title="Set theory">set theory</a>, <b>set-builder notation</b> is a <a href="Mathematical_notation" title="Mathematical notation">notation</a> for specifying a <a href="Set_(mathematics)" title="Set (mathematics)">set</a> by a property that characterizes its members.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>Specifying sets by member properties is allowed by the <a href="Axiom_schema_of_specification" title="Axiom schema of specification">axiom schema of specification</a>. This is also known as <b>set comprehension</b> and <b>set abstraction</b>.
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="Sets_defined_by_a_predicate">Sets defined by a predicate</h2></div>
<p>Set-builder notation can be used to describe a set that is defined by a <a href="Predicate_(mathematical_logic)" class="mw-redirect" title="Predicate (mathematical logic)">predicate</a>, that is, a logical formula that evaluates to <i>true</i> for an element of the set, and <i>false</i> otherwise.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> In this form, set-builder notation has three parts: a variable, a <a href="Colon_(punctuation)" title="Colon (punctuation)">colon</a> or <a href="Vertical_bar" title="Vertical bar">vertical bar</a> separator, and a predicate. Thus there is a variable on the left of the separator, and a rule on the right of it. These three parts are contained in curly brackets:
</p>
<dl><dd><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 \{x\mid \Phi (x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\mid \Phi (x)\}}</annotation>
</semantics>
</math></span><img src="./fc7f6ac571aefc622d3792ddebb869257104f136.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:10.409ex; height:2.843ex;" alt="{\displaystyle \{x\mid \Phi (x)\}}" loading="lazy"></span></dd></dl>
<p>or
</p>
<dl><dd><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 \{x:\Phi (x)\}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>:</mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x:\Phi (x)\}.}</annotation>
</semantics>
</math></span><img src="./38f462eb953a6cca7a9c7a4ae603102a188dd408.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:11.056ex; height:2.843ex;" alt="{\displaystyle \{x:\Phi (x)\}.}" loading="lazy"></span></dd></dl>
<p>The vertical bar (or colon) is a separator that can be read as "<b>such that</b>", "for which", or "with the property that". The formula <span class="texhtml">Φ(<i>x</i>)</span> is said to be the <i>rule</i> or the <i>predicate</i>. All values of <span class="texhtml"><i>x</i></span> for which the predicate holds (is true) belong to the set being defined. All values of <span class="texhtml"><i>x</i></span> for which the predicate does not hold do not belong to the set. Thus <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 \{x\mid \Phi (x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\mid \Phi (x)\}}</annotation>
</semantics>
</math></span><img src="./fc7f6ac571aefc622d3792ddebb869257104f136.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:10.409ex; height:2.843ex;" alt="{\displaystyle \{x\mid \Phi (x)\}}" loading="lazy"></span> is the set of all values of <span class="texhtml"><i>x</i></span> that satisfy the formula <span class="texhtml">Φ</span>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> It may be the <a href="Empty_set" title="Empty set">empty set</a>, if no value of <span class="texhtml"><i>x</i></span> satisfies the formula.
</p>
<div class="mw-heading mw-heading3"><h3 id="Specifying_the_domain">Specifying the domain</h3></div>
<p>A domain <span class="texhtml"><i>E</i></span> can appear on the left of the vertical bar:<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
</p>
<dl><dd><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 \{x\in E\mid \Phi (x)\},}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in E\mid \Phi (x)\},}</annotation>
</semantics>
</math></span><img src="./3b3d31b7fe6a9a12eb0a412f251a9624cb42d981.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.672ex; height:2.843ex;" alt="{\displaystyle \{x\in E\mid \Phi (x)\},}" loading="lazy"></span></dd></dl>
<p>or by adjoining it to the predicate:
</p>
<dl><dd><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 \{x\mid x\in E{\text{ and }}\Phi (x)\}\quad {\text{or}}\quad \{x\mid x\in E\land \Phi (x)\}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∣<!-- ∣ --></mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mrow class="MJX-TeXAtom-ORD">
<mtext>&nbsp;and&nbsp;</mtext>
</mrow>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mspace width="1em"></mspace>
<mrow class="MJX-TeXAtom-ORD">
<mtext>or</mtext>
</mrow>
<mspace width="1em"></mspace>
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∣<!-- ∣ --></mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∧<!-- ∧ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\mid x\in E{\text{ and }}\Phi (x)\}\quad {\text{or}}\quad \{x\mid x\in E\land \Phi (x)\}.}</annotation>
</semantics>
</math></span><img src="./49a118e0efa5fdd6ff35fe0b617f6ab38e11a4ea.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:47.567ex; height:2.843ex;" alt="{\displaystyle \{x\mid x\in E{\text{ and }}\Phi (x)\}\quad {\text{or}}\quad \{x\mid x\in E\land \Phi (x)\}.}" loading="lazy"></span></dd></dl>
<p>The ∈ symbol here denotes <a href="Set_membership" class="mw-redirect" title="Set membership">set membership</a>, while the <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 \land }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo>∧<!-- ∧ --></mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \land }</annotation>
</semantics>
</math></span><img src="./d6823e5a222eb3ca49672818ac3d13ec607052c4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.55ex; height:2.009ex;" alt="{\displaystyle \land }" loading="lazy"></span> symbol denotes the logical "and" operator, known as <a href="Logical_conjunction" title="Logical conjunction">logical conjunction</a>. This notation represents the set of all values of <span class="texhtml"><i>x</i></span> that belong to some given set <span class="texhtml"><i>E</i></span> for which the predicate is true (see "<a href="#Set_existence_axiom">Set existence axiom</a>" below). If <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 \Phi (x)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi (x)}</annotation>
</semantics>
</math></span><img src="./79e4f01c93494fbb5dcd75761f4468121b00b294.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.817ex; height:2.843ex;" alt="{\displaystyle \Phi (x)}" loading="lazy"></span> is a conjunction <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 \Phi _{1}(x)\land \Phi _{2}(x)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>∧<!-- ∧ --></mo>
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \Phi _{1}(x)\land \Phi _{2}(x)}</annotation>
</semantics>
</math></span><img src="./a292f98818d148527a19e4f3e6120dd4170eaf9f.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.325ex; height:2.843ex;" alt="{\displaystyle \Phi _{1}(x)\land \Phi _{2}(x)}" loading="lazy"></span>, then <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 \{x\in E\mid \Phi (x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in E\mid \Phi (x)\}}</annotation>
</semantics>
</math></span><img src="./56f8838e80a235f133c751bc4c3b26ececa685ac.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.025ex; height:2.843ex;" alt="{\displaystyle \{x\in E\mid \Phi (x)\}}" loading="lazy"></span> is sometimes written <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 \{x\in E\mid \Phi _{1}(x),\Phi _{2}(x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∣<!-- ∣ --></mo>
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
<msub>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msub>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in E\mid \Phi _{1}(x),\Phi _{2}(x)\}}</annotation>
</semantics>
</math></span><img src="./8a9382804c62441be0a6ae7202c9da7f0e49f6ac.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:22.985ex; height:2.843ex;" alt="{\displaystyle \{x\in E\mid \Phi _{1}(x),\Phi _{2}(x)\}}" loading="lazy"></span>, using a comma instead of the symbol <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 \land }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo>∧<!-- ∧ --></mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \land }</annotation>
</semantics>
</math></span><img src="./d6823e5a222eb3ca49672818ac3d13ec607052c4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.55ex; height:2.009ex;" alt="{\displaystyle \land }" loading="lazy"></span>.
</p><p>In general, it is not a good idea to consider sets without defining a <a href="Domain_of_discourse" title="Domain of discourse">domain of discourse</a>, as this would represent the <a href="Subset" title="Subset">subset</a> of <i>all possible things that may exist</i> for which the predicate is true. This can easily lead to contradictions and paradoxes. For example, <a href="Russell's_paradox" title="Russell's paradox">Russell's paradox</a> shows that the expression <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 \{x~|~x\not \in x\},}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mtext>&nbsp;</mtext>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mtext>&nbsp;</mtext>
<mi>x</mi>
<mo>∉</mo>
<mi>x</mi>
<mo fence="false" stretchy="false">}</mo>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x~|~x\not \in x\},}</annotation>
</semantics>
</math></span><img src="./f53b7fc3cd6fa07ae176f8e425bd9ac2364acfa7.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:11.61ex; height:2.843ex;" alt="{\displaystyle \{x~|~x\not \in x\},}" loading="lazy"></span> although seemingly well formed as a set builder expression, cannot define a set without producing a contradiction.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup>
</p><p>In cases where the set <span class="texhtml"><i>E</i></span> is clear from context, it may be not explicitly specified. It is common in the literature for an author to state the domain ahead of time, and then not specify it in the set-builder notation. For example, an author may say something such as, "Unless otherwise stated, variables are to be taken to be natural numbers," though in less formal contexts where the domain can be assumed, a written mention is often unnecessary.
</p>
<div class="mw-heading mw-heading3"><h3 id="Examples">Examples</h3></div>
<p>The following examples illustrate particular sets defined by set-builder notation via predicates. In each case, the domain is specified on the left side of the vertical bar, while the rule is specified on the right side.
</p>
<ul><li><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 \{x\in \mathbb {R} \mid x>0\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mi>x</mi>
<mo>&gt;</mo>
<mn>0</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in \mathbb {R} \mid x&gt;0\}}</annotation>
</semantics>
</math></span><img src="./91e0a3d952ba4157408ad6e72933404845089761.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.701ex; height:2.843ex;" alt="{\displaystyle \{x\in \mathbb {R} \mid x>0\}}" loading="lazy"></span> is the set of all strictly <a href="Positive_number" class="mw-redirect" title="Positive number">positive</a> <a href="Real_number" title="Real number">real numbers</a>, which can be written in <a href="Interval_notation" class="mw-redirect" title="Interval notation">interval notation</a> as <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 (0,\infty )}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mn>0</mn>
<mo>,</mo>
<mi mathvariant="normal">∞<!-- ∞ --></mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (0,\infty )}</annotation>
</semantics>
</math></span><img src="./da17102e4ed0886686094ee531df040d2e86352a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:6.329ex; height:2.843ex;" alt="{\displaystyle (0,\infty )}" loading="lazy"></span>.</li>
<li><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 \{x\in \mathbb {R} \mid |x|=1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in \mathbb {R} \mid |x|=1\}}</annotation>
</semantics>
</math></span><img src="./739bee31757c29b0a430e82d7274f55b962d4e68.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:16.995ex; height:2.843ex;" alt="{\displaystyle \{x\in \mathbb {R} \mid |x|=1\}}" loading="lazy"></span> is the set <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 \{-1,1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo>,</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{-1,1\}}</annotation>
</semantics>
</math></span><img src="./c0ffb8c7a09dad8456eee3669ee9a7e462fe3c34.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.492ex; height:2.843ex;" alt="{\displaystyle \{-1,1\}}" loading="lazy"></span>. This set can also be defined as <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 \{x\in \mathbb {R} \mid x^{2}=1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>=</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in \mathbb {R} \mid x^{2}=1\}}</annotation>
</semantics>
</math></span><img src="./775f463b4267457fac55b577395b6b211dc9fe69.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:16.755ex; height:3.176ex;" alt="{\displaystyle \{x\in \mathbb {R} \mid x^{2}=1\}}" loading="lazy"></span>; see <a href="#Equivalent_predicates_yield_equal_sets">equivalent predicates yield equal sets</a> below.</li>
<li>For each integer <span class="texhtml"><i>m</i></span>, we can define <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 G_{m}=\{x\in \mathbb {Z} \mid x\geq m\}=\{m,m+1,m+2,\ldots \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>G</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
</mrow>
</msub>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mi>x</mi>
<mo>≥<!-- ≥ --></mo>
<mi>m</mi>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>m</mi>
<mo>,</mo>
<mi>m</mi>
<mo>+</mo>
<mn>1</mn>
<mo>,</mo>
<mi>m</mi>
<mo>+</mo>
<mn>2</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle G_{m}=\{x\in \mathbb {Z} \mid x\geq m\}=\{m,m+1,m+2,\ldots \}}</annotation>
</semantics>
</math></span><img src="./3e6b318b1769ab0c58bbd749afa1a34882de85fe.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:48.427ex; height:2.843ex;" alt="{\displaystyle G_{m}=\{x\in \mathbb {Z} \mid x\geq m\}=\{m,m+1,m+2,\ldots \}}" loading="lazy"></span>. As an example, <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 G_{3}=\{x\in \mathbb {Z} \mid x\geq 3\}=\{3,4,5,\ldots \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>G</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msub>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mi>x</mi>
<mo>≥<!-- ≥ --></mo>
<mn>3</mn>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mn>3</mn>
<mo>,</mo>
<mn>4</mn>
<mo>,</mo>
<mn>5</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle G_{3}=\{x\in \mathbb {Z} \mid x\geq 3\}=\{3,4,5,\ldots \}}</annotation>
</semantics>
</math></span><img src="./0cf668c1e0463567c2c2578662c1e7706f2625e0.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:36.289ex; height:2.843ex;" alt="{\displaystyle G_{3}=\{x\in \mathbb {Z} \mid x\geq 3\}=\{3,4,5,\ldots \}}" loading="lazy"></span> and <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 G_{-2}=\{-2,-1,0,\ldots \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mi>G</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>−<!-- − --></mo>
<mn>2</mn>
</mrow>
</msub>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mo>,</mo>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo>,</mo>
<mn>0</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle G_{-2}=\{-2,-1,0,\ldots \}}</annotation>
</semantics>
</math></span><img src="./880004f1c2bc687a3b1b04301f925d7ca64c5676.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:22.512ex; height:2.843ex;" alt="{\displaystyle G_{-2}=\{-2,-1,0,\ldots \}}" loading="lazy"></span>.</li>
<li><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 \{(x,y)\in \mathbb {R} \times \mathbb {R} \mid 0<y<f(x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo stretchy="false">)</mo>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>×<!-- × --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mn>0</mn>
<mo>&lt;</mo>
<mi>y</mi>
<mo>&lt;</mo>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{(x,y)\in \mathbb {R} \times \mathbb {R} \mid 0&lt;y&lt;f(x)\}}</annotation>
</semantics>
</math></span><img src="./f875581ef48fc23f6041506cad847cda66a04180.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:31.56ex; height:2.843ex;" alt="{\displaystyle \{(x,y)\in \mathbb {R} \times \mathbb {R} \mid 0<y<f(x)\}}" loading="lazy"></span> is the set of pairs of real numbers such that <i>y</i> is greater than 0 and less than <span class="texhtml"><i>f</i>(<i>x</i>)</span>, for a given <a href="Function_(mathematics)" title="Function (mathematics)">function</a> <span class="texhtml"><i>f</i></span>. Here the <a href="Cartesian_product" title="Cartesian product">cartesian product</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 \mathbb {R} \times \mathbb {R} }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>×<!-- × --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathbb {R} \times \mathbb {R} }</annotation>
</semantics>
</math></span><img src="./eb99f01c438a62e4ac5af8cff4eb402739ed67a8.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:6.197ex; height:2.176ex;" alt="{\displaystyle \mathbb {R} \times \mathbb {R} }" loading="lazy"></span> denotes the set of ordered pairs of real numbers.</li>
<li><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 \{n\in \mathbb {N} \mid (\exists k)[k\in \mathbb {N} \land n=2k]\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>n</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">N</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>k</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">[</mo>
<mi>k</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">N</mi>
</mrow>
<mo>∧<!-- ∧ --></mo>
<mi>n</mi>
<mo>=</mo>
<mn>2</mn>
<mi>k</mi>
<mo stretchy="false">]</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{n\in \mathbb {N} \mid (\exists k)[k\in \mathbb {N} \land n=2k]\}}</annotation>
</semantics>
</math></span><img src="./5a46338b7739df2ad6f24c515613810639c73439.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:30.962ex; height:2.843ex;" alt="{\displaystyle \{n\in \mathbb {N} \mid (\exists k)[k\in \mathbb {N} \land n=2k]\}}" loading="lazy"></span> is the set of all <a href="Even_number" class="mw-redirect" title="Even number">even</a> <a href="Natural_number" title="Natural number">natural numbers</a>. The <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 \land }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo>∧<!-- ∧ --></mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \land }</annotation>
</semantics>
</math></span><img src="./d6823e5a222eb3ca49672818ac3d13ec607052c4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.55ex; height:2.009ex;" alt="{\displaystyle \land }" loading="lazy"></span> sign stands for "and", which is known as <a href="Logical_conjunction" title="Logical conjunction">logical conjunction</a>. The ∃ sign stands for "there exists", which is known as <a href="Existential_quantification" title="Existential quantification">existential quantification</a>. So for example, <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 (\exists x)P(x)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mi>P</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (\exists x)P(x)}</annotation>
</semantics>
</math></span><img src="./8b97f48e1a2037bb39ad6f54fb60acc01c62c2c4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:9.316ex; height:2.843ex;" alt="{\displaystyle (\exists x)P(x)}" loading="lazy"></span> is read as "there exists an <span class="texhtml"><i>x</i></span> such that <span class="texhtml"><i>P</i>(<i>x</i>)</span>".</li>
<li><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 \{n\mid (\exists k\in \mathbb {N} )[n=2k]\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>n</mi>
<mo>∣<!-- ∣ --></mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>k</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">N</mi>
</mrow>
<mo stretchy="false">)</mo>
<mo stretchy="false">[</mo>
<mi>n</mi>
<mo>=</mo>
<mn>2</mn>
<mi>k</mi>
<mo stretchy="false">]</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{n\mid (\exists k\in \mathbb {N} )[n=2k]\}}</annotation>
</semantics>
</math></span><img src="./701ae3a0b2195e3749d19cdc48f21418042dbd00.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:22.649ex; height:2.843ex;" alt="{\displaystyle \{n\mid (\exists k\in \mathbb {N} )[n=2k]\}}" loading="lazy"></span> is a notational variant for the same set of even natural numbers. It is not necessary to specify that <span class="texhtml"><i>n</i></span> is a natural number, as this is implied by the formula on the right.</li>
<li><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\in \mathbb {R} \mid (\exists p\in \mathbb {Z} )(\exists q\in \mathbb {Z} )[q\not =0\land aq=p]\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>a</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>p</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>q</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo stretchy="false">)</mo>
<mo stretchy="false">[</mo>
<mi>q</mi>
<mo>≠</mo>
<mn>0</mn>
<mo>∧<!-- ∧ --></mo>
<mi>a</mi>
<mi>q</mi>
<mo>=</mo>
<mi>p</mi>
<mo stretchy="false">]</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{a\in \mathbb {R} \mid (\exists p\in \mathbb {Z} )(\exists q\in \mathbb {Z} )[q\not =0\land aq=p]\}}</annotation>
</semantics>
</math></span><img src="./4aaa130fdd174335a4c527fe7e7aa62e723642c0.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:43.009ex; height:2.843ex;" alt="{\displaystyle \{a\in \mathbb {R} \mid (\exists p\in \mathbb {Z} )(\exists q\in \mathbb {Z} )[q\not =0\land aq=p]\}}" loading="lazy"></span> is the set of <a href="Rational_number" title="Rational number">rational numbers</a>; that is, real numbers that can be written as the ratio of two <a href="Integer" title="Integer">integers</a>.</li></ul>
<div class="mw-heading mw-heading2"><h2 id="More_complex_expressions_on_the_left_side_of_the_notation">More complex expressions on the left side of the notation</h2></div>
<p>An extension of set-builder notation replaces the single variable <span class="texhtml"><i>x</i></span> with an <a href="Expression_(mathematics)" title="Expression (mathematics)">expression</a>. So instead of <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 \{x\mid \Phi (x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\mid \Phi (x)\}}</annotation>
</semantics>
</math></span><img src="./fc7f6ac571aefc622d3792ddebb869257104f136.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:10.409ex; height:2.843ex;" alt="{\displaystyle \{x\mid \Phi (x)\}}" loading="lazy"></span>, we may have <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 \{f(x)\mid \Phi (x)\},}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{f(x)\mid \Phi (x)\},}</annotation>
</semantics>
</math></span><img src="./48aa87f275c9701a8584a05ce832acc150e8eb52.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.144ex; height:2.843ex;" alt="{\displaystyle \{f(x)\mid \Phi (x)\},}" loading="lazy"></span> which should be read
</p>
<dl><dd><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 \{f(x)\mid \Phi (x)\}=\{y\mid \exists x(y=f(x)\wedge \Phi (x))\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>y</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>x</mi>
<mo stretchy="false">(</mo>
<mi>y</mi>
<mo>=</mo>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>∧<!-- ∧ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{f(x)\mid \Phi (x)\}=\{y\mid \exists x(y=f(x)\wedge \Phi (x))\}}</annotation>
</semantics>
</math></span><img src="./8037be64f0b135ade9480f0ea17af58b1e88df27.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:42.515ex; height:2.843ex;" alt="{\displaystyle \{f(x)\mid \Phi (x)\}=\{y\mid \exists x(y=f(x)\wedge \Phi (x))\}}" loading="lazy"></span>.</dd></dl>
<p>For example:
</p>
<ul><li><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 \{2n\mid n\in \mathbb {N} \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mn>2</mn>
<mi>n</mi>
<mo>∣<!-- ∣ --></mo>
<mi>n</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">N</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{2n\mid n\in \mathbb {N} \}}</annotation>
</semantics>
</math></span><img src="./8ce92765655dbc7b1b726f07683c5448f0b43c7d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:12.733ex; height:2.843ex;" alt="{\displaystyle \{2n\mid n\in \mathbb {N} \}}" loading="lazy"></span>, 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 \mathbb {N} }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">N</mi>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathbb {N} }</annotation>
</semantics>
</math></span><img src="./fdf9a96b565ea202d0f4322e9195613fb26a9bed.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.678ex; height:2.176ex;" alt="{\displaystyle \mathbb {N} }" loading="lazy"></span> is the set of all natural numbers, is the set of all even natural numbers.</li>
<li><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 \{p/q\mid p,q\in \mathbb {Z} ,q\not =0\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>p</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>q</mi>
<mo>∣<!-- ∣ --></mo>
<mi>p</mi>
<mo>,</mo>
<mi>q</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo>,</mo>
<mi>q</mi>
<mo>≠</mo>
<mn>0</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{p/q\mid p,q\in \mathbb {Z} ,q\not =0\}}</annotation>
</semantics>
</math></span><img src="./b5ac1cae555e4634488a2b19bf3feafdf30e0df5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:21.692ex; height:2.843ex;" alt="{\displaystyle \{p/q\mid p,q\in \mathbb {Z} ,q\not =0\}}" loading="lazy"></span>, 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 \mathbb {Z} }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathbb {Z} }</annotation>
</semantics>
</math></span><img src="./449494a083e0a1fda2b61c62b2f09b6bee4633dc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.55ex; height:2.176ex;" alt="{\displaystyle \mathbb {Z} }" loading="lazy"></span> is the set of all integers, is <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 \mathbb {Q} ,}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Q</mi>
</mrow>
<mo>,</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathbb {Q} ,}</annotation>
</semantics>
</math></span><img src="./91185244fbdded6ea99a5e9e6603299128b10928.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.455ex; height:2.509ex;" alt="{\displaystyle \mathbb {Q} ,}" loading="lazy"></span> the set of all rational numbers.</li>
<li><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 \{2t+1\mid t\in \mathbb {Z} \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mn>2</mn>
<mi>t</mi>
<mo>+</mo>
<mn>1</mn>
<mo>∣<!-- ∣ --></mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}}</annotation>
</semantics>
</math></span><img src="./778c2185ece69ae5912d3ec1c41c0a9371025bbd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.498ex; height:2.843ex;" alt="{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}}" loading="lazy"></span> is the set of odd integers.</li>
<li><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 \{(t,2t+1)\mid t\in \mathbb {Z} \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo>,</mo>
<mn>2</mn>
<mi>t</mi>
<mo>+</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>∣<!-- ∣ --></mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{(t,2t+1)\mid t\in \mathbb {Z} \}}</annotation>
</semantics>
</math></span><img src="./62feaf63e58cd386b828b28eccd58ce2dd0bb067.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:19.18ex; height:2.843ex;" alt="{\displaystyle \{(t,2t+1)\mid t\in \mathbb {Z} \}}" loading="lazy"></span> creates a set of pairs, where each pair puts an integer into correspondence with an odd integer.</li></ul>
<p>When inverse functions can be explicitly stated, the expression on the left can be eliminated through simple substitution. Consider the example set <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 \{2t+1\mid t\in \mathbb {Z} \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mn>2</mn>
<mi>t</mi>
<mo>+</mo>
<mn>1</mn>
<mo>∣<!-- ∣ --></mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}}</annotation>
</semantics>
</math></span><img src="./778c2185ece69ae5912d3ec1c41c0a9371025bbd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.498ex; height:2.843ex;" alt="{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}}" loading="lazy"></span>. Make the substitution <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 u=2t+1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>u</mi>
<mo>=</mo>
<mn>2</mn>
<mi>t</mi>
<mo>+</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle u=2t+1}</annotation>
</semantics>
</math></span><img src="./f8edda6a9a8c3731e56db7676aa4991c02f2a832.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:10.433ex; height:2.343ex;" alt="{\displaystyle u=2t+1}" loading="lazy"></span>, which is to say <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 t=(u-1)/2}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>t</mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<mi>u</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>2</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle t=(u-1)/2}</annotation>
</semantics>
</math></span><img src="./5b2dd0563394c8180c8abcd7106f2b5b2f3609f3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:13.405ex; height:2.843ex;" alt="{\displaystyle t=(u-1)/2}" loading="lazy"></span>, then replace <i>t</i> in the set builder notation to find
</p>
<dl><dd><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 \{2t+1\mid t\in \mathbb {Z} \}=\{u\mid (u-1)/2\in \mathbb {Z} \}.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mn>2</mn>
<mi>t</mi>
<mo>+</mo>
<mn>1</mn>
<mo>∣<!-- ∣ --></mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>u</mi>
<mo>∣<!-- ∣ --></mo>
<mo stretchy="false">(</mo>
<mi>u</mi>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mn>2</mn>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Z</mi>
</mrow>
<mo fence="false" stretchy="false">}</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}=\{u\mid (u-1)/2\in \mathbb {Z} \}.}</annotation>
</semantics>
</math></span><img src="./326b8b16c6c6e171ceb9999f95d8a4bebb9a4433.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:38.692ex; height:2.843ex;" alt="{\displaystyle \{2t+1\mid t\in \mathbb {Z} \}=\{u\mid (u-1)/2\in \mathbb {Z} \}.}" loading="lazy"></span></dd></dl>
<div class="mw-heading mw-heading2"><h2 id="Equivalent_predicates_yield_equal_sets">Equivalent predicates yield equal sets</h2></div>
<p>Two sets are equal if and only if they have the same elements. Sets defined by set builder notation are equal if and only if their set builder rules, including the domain specifiers, are equivalent. That is
</p>
<dl><dd><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 \{x\in A\mid P(x)\}=\{x\in B\mid Q(x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>A</mi>
<mo>∣<!-- ∣ --></mo>
<mi>P</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>B</mi>
<mo>∣<!-- ∣ --></mo>
<mi>Q</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in A\mid P(x)\}=\{x\in B\mid Q(x)\}}</annotation>
</semantics>
</math></span><img src="./8b98c815026a915a2104deed3b354a242833ea2f.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:33.332ex; height:2.843ex;" alt="{\displaystyle \{x\in A\mid P(x)\}=\{x\in B\mid Q(x)\}}" loading="lazy"></span></dd></dl>
<p>if and only if
</p>
<dl><dd><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 (\forall t)[(t\in A\land P(t))\Leftrightarrow (t\in B\land Q(t))]}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∀<!-- ∀ --></mi>
<mi>t</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">[</mo>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mi>A</mi>
<mo>∧<!-- ∧ --></mo>
<mi>P</mi>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
<mo stretchy="false">⇔<!-- ⇔ --></mo>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mi>B</mi>
<mo>∧<!-- ∧ --></mo>
<mi>Q</mi>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">)</mo>
<mo stretchy="false">]</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (\forall t)[(t\in A\land P(t))\Leftrightarrow (t\in B\land Q(t))]}</annotation>
</semantics>
</math></span><img src="./658c37b78c51b9bbf5310d58c1497a0ebfaf95e3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:37.382ex; height:2.843ex;" alt="{\displaystyle (\forall t)[(t\in A\land P(t))\Leftrightarrow (t\in B\land Q(t))]}" loading="lazy"></span>.</dd></dl>
<p>Therefore, in order to prove the equality of two sets defined by set builder notation, it suffices to prove the equivalence of their predicates, including the domain qualifiers.
</p><p>For example,
</p>
<dl><dd><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 \{x\in \mathbb {R} \mid x^{2}=1\}=\{x\in \mathbb {Q} \mid |x|=1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>=</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Q</mi>
</mrow>
<mo>∣<!-- ∣ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in \mathbb {R} \mid x^{2}=1\}=\{x\in \mathbb {Q} \mid |x|=1\}}</annotation>
</semantics>
</math></span><img src="./e092f38e7fcabebc72f44fce0ffa388b5decba5c.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:36.979ex; height:3.176ex;" alt="{\displaystyle \{x\in \mathbb {R} \mid x^{2}=1\}=\{x\in \mathbb {Q} \mid |x|=1\}}" loading="lazy"></span></dd></dl>
<p>because the two rule predicates are logically equivalent:
</p>
<dl><dd><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 (x\in \mathbb {R} \land x^{2}=1)\Leftrightarrow (x\in \mathbb {Q} \land |x|=1).}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mo>∧<!-- ∧ --></mo>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>=</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo stretchy="false">⇔<!-- ⇔ --></mo>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">Q</mi>
</mrow>
<mo>∧<!-- ∧ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mo stretchy="false">)</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (x\in \mathbb {R} \land x^{2}=1)\Leftrightarrow (x\in \mathbb {Q} \land |x|=1).}</annotation>
</semantics>
</math></span><img src="./a1bcf70ce4b0cc8f86e57d13c716490d68f8003a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:38.401ex; height:3.176ex;" alt="{\displaystyle (x\in \mathbb {R} \land x^{2}=1)\Leftrightarrow (x\in \mathbb {Q} \land |x|=1).}" loading="lazy"></span></dd></dl>
<p>This equivalence holds because, for any real number <i>x</i>, we have <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 x^{2}=1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>=</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle x^{2}=1}</annotation>
</semantics>
</math></span><img src="./51e28d7561fa4fe556f438b88380ef98c5631cf5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:6.645ex; height:2.676ex;" alt="{\displaystyle x^{2}=1}" loading="lazy"></span> if and only if <i>x</i> is a rational number with <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 |x|=1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle |x|=1}</annotation>
</semantics>
</math></span><img src="./a6af0ada8d94dff5f2130cc4ea61c6559294b85e.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:6.884ex; height:2.843ex;" alt="{\displaystyle |x|=1}" loading="lazy"></span>. In particular, both sets are equal to the set <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 \{-1,1\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mo>−<!-- − --></mo>
<mn>1</mn>
<mo>,</mo>
<mn>1</mn>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{-1,1\}}</annotation>
</semantics>
</math></span><img src="./c0ffb8c7a09dad8456eee3669ee9a7e462fe3c34.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.492ex; height:2.843ex;" alt="{\displaystyle \{-1,1\}}" loading="lazy"></span>.
</p>
<div class="mw-heading mw-heading2"><h2 id="Set_existence_axiom">Set existence axiom</h2></div>
<p>In many formal set theories, such as <a href="Zermelo%E2%80%93Fraenkel_set_theory" title="Zermelo–Fraenkel set theory">Zermelo–Fraenkel set theory</a>, set builder notation is not part of the formal syntax of the theory. Instead, there is a <a href="Axiom_of_comprehension" class="mw-redirect" title="Axiom of comprehension">set existence axiom scheme</a>, which states that if <span class="texhtml"><i>E</i></span> is a set and <span class="texhtml">Φ(<i>x</i>)</span> is a formula in the language of set theory, then there is a set <span class="texhtml"><i>Y</i></span> whose members are exactly the elements of <span class="texhtml"><i>E</i></span> that satisfy <span class="texhtml">Φ</span>:
</p>
<dl><dd><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 (\forall E)(\exists Y)(\forall x)[x\in Y\Leftrightarrow x\in E\land \Phi (x)].}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∀<!-- ∀ --></mi>
<mi>E</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∃<!-- ∃ --></mi>
<mi>Y</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi mathvariant="normal">∀<!-- ∀ --></mi>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">[</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>Y</mi>
<mo stretchy="false">⇔<!-- ⇔ --></mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∧<!-- ∧ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">]</mo>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (\forall E)(\exists Y)(\forall x)[x\in Y\Leftrightarrow x\in E\land \Phi (x)].}</annotation>
</semantics>
</math></span><img src="./c5bfce627bbb50ca3adaad3102bc95e34e9d9862.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:39.028ex; height:2.843ex;" alt="{\displaystyle (\forall E)(\exists Y)(\forall x)[x\in Y\Leftrightarrow x\in E\land \Phi (x)].}" loading="lazy"></span></dd></dl>
<p>The set <span class="texhtml"><i>Y</i></span> obtained from this axiom is exactly the set described in set builder notation as <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 \{x\in E\mid \Phi (x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>E</mi>
<mo>∣<!-- ∣ --></mo>
<mi mathvariant="normal">Φ<!-- Φ --></mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{x\in E\mid \Phi (x)\}}</annotation>
</semantics>
</math></span><img src="./56f8838e80a235f133c751bc4c3b26ececa685ac.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.025ex; height:2.843ex;" alt="{\displaystyle \{x\in E\mid \Phi (x)\}}" loading="lazy"></span>.
</p>
<div class="mw-heading mw-heading2"><h2 id="In_programming_languages">In programming languages</h2></div>
<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">Main article: <a href="List_comprehension" title="List comprehension">List comprehension</a></div>
<p>A similar notation available in a number of <a href="Programming_languages" class="mw-redirect" title="Programming languages">programming languages</a> (notably <a href="Python_(programming_language)" title="Python (programming language)">Python</a> and <a href="Haskell_(programming_language)" class="mw-redirect" title="Haskell (programming language)">Haskell</a>) is the <a href="List_comprehension" title="List comprehension">list comprehension</a>, which combines <a href="Map_(higher-order_function)" title="Map (higher-order function)">map</a> and <a href="Filter_(higher-order_function)" title="Filter (higher-order function)">filter</a> operations over one or more <a href="List_(computing)" class="mw-redirect" title="List (computing)">lists</a>.
</p>
<style data-mw-deduplicate="TemplateStyles:r1305433154">
/* start https://en.wikipedia.org/ */


.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}


/* end https://en.wikipedia.org/ */
</style>
<p>In Python, the set-builder's braces are replaced with square brackets, parentheses, or curly braces, giving list, <a href="Generator_(computer_science)" class="mw-redirect" title="Generator (computer science)">generator</a>, and set objects, respectively. Python uses an English-based syntax. Haskell replaces the set-builder's braces with square brackets and uses symbols, including the standard set-builder vertical bar.
</p><p>The same can be achieved in <a href="Scala_(programming_language)" title="Scala (programming language)">Scala</a> using Sequence Comprehensions, where the "for" keyword returns a list of the yielded variables using the "yield" keyword.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup>
</p><p>Consider these set-builder notation examples in some programming languages:
</p>
<table class="wikitable">

<tbody><tr>
<th></th>
<th>Example 1</th>
<th>Example 2
</th></tr>
<tr style="text-align:center;">
<th>Set-builder
</th>
<td><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 \{l\ |\ l\in L\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mi>l</mi>
<mtext>&nbsp;</mtext>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mtext>&nbsp;</mtext>
<mi>l</mi>
<mo>∈<!-- ∈ --></mo>
<mi>L</mi>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{l\ |\ l\in L\}}</annotation>
</semantics>
</math></span><img src="./6d05d0641bb3cc7a11c0cedf017c032eeef0291d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:9.943ex; height:2.843ex;" alt="{\displaystyle \{l\ |\ l\in L\}}" loading="lazy"></span></td>
<td><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 \{(k,x)\ |\ k\in K\wedge x\in X\wedge P(x)\}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">{</mo>
<mo stretchy="false">(</mo>
<mi>k</mi>
<mo>,</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mtext>&nbsp;</mtext>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mtext>&nbsp;</mtext>
<mi>k</mi>
<mo>∈<!-- ∈ --></mo>
<mi>K</mi>
<mo>∧<!-- ∧ --></mo>
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mi>X</mi>
<mo>∧<!-- ∧ --></mo>
<mi>P</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo fence="false" stretchy="false">}</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \{(k,x)\ |\ k\in K\wedge x\in X\wedge P(x)\}}</annotation>
</semantics>
</math></span><img src="./e2a774243ad8269f996d957f0be4b09dda8dc7b5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:31.835ex; height:2.843ex;" alt="{\displaystyle \{(k,x)\ |\ k\in K\wedge x\in X\wedge P(x)\}}" loading="lazy"></span>
</td></tr>
<tr>
<th scope="row"><a href="Python_(programming_language)" title="Python (programming language)">Python</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-python mw-content-ltr" dir="ltr"><pre><span class="p">{</span><span class="n">l</span> <span class="k">for</span> <span class="n">l</span> <span class="ow">in</span> <span class="n">L</span><span class="p">}</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-python mw-content-ltr" dir="ltr"><pre><span class="p">{(</span><span class="n">k</span><span class="p">,</span> <span class="n">x</span><span class="p">)</span> <span class="k">for</span> <span class="n">k</span> <span class="ow">in</span> <span class="n">K</span> <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">X</span> <span class="k">if</span> <span class="n">P</span><span class="p">(</span><span class="n">x</span><span class="p">)}</span>
</pre></div>
</td></tr>
<tr>
<th scope="row"><a href="Haskell_(programming_language)" class="mw-redirect" title="Haskell (programming language)">Haskell</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-haskell mw-content-ltr" dir="ltr"><pre><span class="p">[</span><span class="n">l</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">l</span><span class="w"> </span><span class="ow">&lt;-</span><span class="w"> </span><span class="n">ls</span><span class="p">]</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-haskell mw-content-ltr" dir="ltr"><pre><span class="p">[(</span><span class="n">k</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="o">|</span><span class="w"> </span><span class="n">k</span><span class="w"> </span><span class="ow">&lt;-</span><span class="w"> </span><span class="n">ks</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="ow">&lt;-</span><span class="w"> </span><span class="n">xs</span><span class="p">,</span><span class="w"> </span><span class="n">p</span><span class="w"> </span><span class="n">x</span><span class="p">]</span>
</pre></div>
</td></tr>
<tr>
<th scope="row"><a href="Scala_(programming_language)" title="Scala (programming language)">Scala</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-scala mw-content-ltr" dir="ltr"><pre><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">l</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nc">L</span><span class="p">)</span><span class="w"> </span><span class="k">yield</span><span class="w"> </span><span class="n">l</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-scala mw-content-ltr" dir="ltr"><pre><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n">k</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nc">K</span><span class="p">;</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nc">X</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nc">P</span><span class="p">(</span><span class="n">x</span><span class="p">))</span><span class="w"> </span><span class="k">yield</span><span class="w"> </span><span class="p">(</span><span class="n">k</span><span class="p">,</span><span class="n">x</span><span class="p">)</span>
</pre></div>
</td></tr>
<tr>
<th scope="row"><a href="C_Sharp_(programming_language)" title="C Sharp (programming language)">C#</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-csharp mw-content-ltr" dir="ltr"><pre><span class="k">from</span><span class="w"> </span><span class="n">l</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">L</span><span class="w"> </span><span class="k">select</span><span class="w"> </span><span class="n">l</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-csharp mw-content-ltr" dir="ltr"><pre><span class="k">from</span><span class="w"> </span><span class="n">k</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">K</span><span class="w"> </span><span class="k">from</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="n">X</span><span class="w"> </span><span class="k">where</span><span class="w"> </span><span class="nf">P</span><span class="p">(</span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="k">select</span><span class="w"> </span><span class="p">(</span><span class="n">k</span><span class="p">,</span><span class="n">x</span><span class="p">)</span>
</pre></div>
</td></tr>
<tr>
<th scope="row"><a href="SQL" title="SQL">SQL</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span class="k">SELECT</span><span class="w"> </span><span class="n">l</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">L_set</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-sql mw-content-ltr" dir="ltr"><pre><span class="w"> </span><span class="k">SELECT</span><span class="w"> </span><span class="n">k</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">K_set</span><span class="p">,</span><span class="w"> </span><span class="n">X_set</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">P</span><span class="p">(</span><span class="n">x</span><span class="p">)</span>
</pre></div>
</td></tr>
<tr>
<th scope="row"><a href="Prolog" title="Prolog">Prolog</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre><span class="nf">setof</span><span class="p">(</span><span class="nv">L</span><span class="p">,</span><span class="nf">member</span><span class="p">(</span><span class="nv">L</span><span class="p">,</span><span class="nv">Ls</span><span class="p">),</span><span class="nv">Result</span><span class="p">)</span>
</pre></div></td>
<td><div class="mw-highlight mw-highlight-lang-prolog mw-content-ltr" dir="ltr"><pre><span class="nf">setof</span><span class="p">((</span><span class="nv">K</span><span class="p">,</span><span class="nv">X</span><span class="p">),(</span><span class="nf">member</span><span class="p">(</span><span class="nv">K</span><span class="p">,</span><span class="nv">Ks</span><span class="p">),</span><span class="nf">member</span><span class="p">(</span><span class="nv">X</span><span class="p">,</span><span class="nv">Xs</span><span class="p">),</span><span class="nf">call</span><span class="p">(</span><span class="nv">P</span><span class="p">,</span><span class="nv">X</span><span class="p">)),</span><span class="nv">Result</span><span class="p">)</span>
</pre></div>
</td></tr>
<tr>
<th><a href="Erlang_(programming_language)" title="Erlang (programming language)">Erlang</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-erlang mw-content-ltr" dir="ltr"><pre><span class="p">[</span><span class="nv">L</span><span class="w"> </span><span class="p">||</span><span class="w"> </span><span class="nv">L</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nv">Ls</span><span class="p">]</span>
</pre></div>
</td>
<td><div class="mw-highlight mw-highlight-lang-erlang mw-content-ltr" dir="ltr"><pre><span class="p">[{</span><span class="nv">K</span><span class="p">,</span><span class="nv">X</span><span class="p">}</span><span class="w"> </span><span class="p">||</span><span class="w"> </span><span class="nv">K</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nv">Ks</span><span class="p">,</span><span class="w"> </span><span class="nv">X</span><span class="w"> </span><span class="o">&lt;-</span><span class="w"> </span><span class="nv">Xs</span><span class="p">,</span><span class="w"> </span><span class="n">p</span><span class="p">(</span><span class="nv">X</span><span class="p">)]</span>
</pre></div>
</td></tr>
<tr>
<th><a href="Julia_(programming_language)" title="Julia (programming language)">Julia</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-julia mw-content-ltr" dir="ltr"><pre><span class="p">[</span><span class="n">l</span><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">l</span><span class="w"> </span><span class="o">∈</span><span class="w"> </span><span class="n">L</span><span class="p">]</span>
</pre></div>
</td>
<td><div class="mw-highlight mw-highlight-lang-julia mw-content-ltr" dir="ltr"><pre><span class="p">[(</span><span class="n">k</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">k</span><span class="w"> </span><span class="o">∈</span><span class="w"> </span><span class="n">K</span><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">x</span><span class="w"> </span><span class="o">∈</span><span class="w"> </span><span class="n">X</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">P</span><span class="p">(</span><span class="n">x</span><span class="p">)]</span>
</pre></div>
</td></tr>
<tr>
<th><a href="Wolfram_Mathematica" class="mw-redirect" title="Wolfram Mathematica">Mathematica</a>
</th>
<td><div class="mw-highlight mw-highlight-lang-mathematica mw-content-ltr" dir="ltr"><pre><span class="p">(</span><span class="n">l</span><span class="w"> </span><span class="o">|-&gt;</span><span class="w"> </span><span class="n">l</span><span class="p">)</span><span class="w"> </span><span class="o">/@</span><span class="w"> </span><span class="n">L</span>
</pre></div>
</td>
<td><div class="mw-highlight mw-highlight-lang-mathematica mw-content-ltr" dir="ltr"><pre><span class="n">Cases</span><span class="p">[</span><span class="n">Tuples</span><span class="p">[{</span><span class="n">K</span><span class="p">,</span><span class="w"> </span><span class="n">X</span><span class="p">}],</span><span class="w"> </span><span class="p">{</span><span class="nv">k_</span><span class="p">,</span><span class="w"> </span><span class="nv">x_</span><span class="p">}</span><span class="w"> </span><span class="o">/;</span><span class="w"> </span><span class="n">P</span><span class="p">[</span><span class="n">x</span><span class="p">]]</span>
</pre></div>
</td></tr></tbody></table>
<p>The set builder notation and list comprehension notation are both instances of a more general notation known as <i>monad comprehensions</i>, which permits map/filter-like operations over any <a href="Monad_(functional_programming)" title="Monad (functional programming)">monad</a> with a <a href="Zero_element" title="Zero element">zero element</a>.
</p>
<div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div>
<ul><li><a href="Glossary_of_set_theory" title="Glossary of set theory">Glossary of set theory</a></li></ul>
<div class="mw-heading mw-heading2"><h2 id="Notes">Notes</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-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</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="CITEREFRosen2007" class="citation book cs1">Rosen, Kenneth (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ZYZfQgAACAAJ&amp;pg=PA111"><i>Discrete Mathematics and its Applications</i></a> (6th&nbsp;ed.). New York, NY: McGraw-Hill. pp.&nbsp;<span class="nowrap">111–</span>112. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a>&nbsp;<bdi>978-0-07-288008-3</bdi>.</cite></span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">Michael J Cullinan, 2012, <i>A Transition to Mathematics with Proofs</i>, Jones &amp; Bartlett, pp.&nbsp;44ff.</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"><cite id="CITEREFWeisstein" class="citation web cs1">Weisstein, Eric W. <a rel="nofollow" class="external text" href="https://mathworld.wolfram.com/Set.html">"Set"</a>. <i>mathworld.wolfram.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">20 August</span> 2020</span>.</cite></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 class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.mathsisfun.com/sets/set-builder-notation.html">"Set-Builder Notation"</a>. <i>mathsisfun.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">20 August</span> 2020</span>.</cite></span>
</li>
<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><cite id="CITEREFIrvineDeutsch2016" class="citation encyclopaedia cs1">Irvine, Andrew David; Deutsch, Harry (9 October 2016) [1995]. <a rel="nofollow" class="external text" href="http://plato.stanford.edu/entries/russell-paradox/">"Russell's Paradox"</a>. <i>Stanford Encyclopedia of Philosophy</i><span class="reference-accessdate">. Retrieved <span class="nowrap">6 August</span> 2017</span>.</cite></span>
</li>
<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://docs.scala-lang.org/tutorials/tour/sequence-comprehensions.html">"Sequence Comprehensions"</a>. Scala<span class="reference-accessdate">. Retrieved <span class="nowrap">6 August</span> 2017</span>.</cite></span>
</li>
</ol></div></div>
<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="Set_theory409" style="padding:3px"><table class="nowraplinks mw-collapsible mw-collapsed 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="Set_theory409" style="font-size:114%;margin:0 4em"><a href="Set_theory" title="Set theory">Set theory</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Overview</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="Set_(mathematics)" title="Set (mathematics)">Set (mathematics)</a></li></ul>
</div></td><td class="noviewer navbox-image" rowspan="8" style="width:1px;padding:0 0 0 2px"><div><span typeof="mw:File"><a href="Venn_diagram" title="Venn diagram"></a></span></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Axiom" title="Axiom">Axioms</a></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="Axiom_of_adjunction" title="Axiom of adjunction">Adjunction</a></li>
<li><a href="Axiom_of_choice" title="Axiom of choice">Choice</a>
<ul><li><a href="Axiom_of_countable_choice" title="Axiom of countable choice">countable</a></li>
<li><a href="Axiom_of_dependent_choice" title="Axiom of dependent choice">dependent</a></li>
<li><a href="Axiom_of_global_choice" title="Axiom of global choice">global</a></li></ul></li>
<li><a href="Axiom_of_constructibility" title="Axiom of constructibility">Constructibility (V=L)</a></li>
<li><a href="Axiom_of_determinacy" title="Axiom of determinacy">Determinacy</a>
<ul><li><a href="Axiom_of_projective_determinacy" class="mw-redirect" title="Axiom of projective determinacy">projective</a></li></ul></li>
<li><a href="Axiom_of_extensionality" title="Axiom of extensionality">Extensionality</a></li>
<li><a href="Axiom_of_infinity" title="Axiom of infinity">Infinity</a></li>
<li><a href="Axiom_of_limitation_of_size" title="Axiom of limitation of size">Limitation of size</a></li>
<li><a href="Axiom_of_pairing" title="Axiom of pairing">Pairing</a></li>
<li><a href="Axiom_of_power_set" title="Axiom of power set">Power set</a></li>
<li><a href="Axiom_of_regularity" title="Axiom of regularity">Regularity</a></li>
<li><a href="Axiom_of_union" title="Axiom of union">Union</a></li>
<li><a href="Martin's_axiom" title="Martin's axiom">Martin's axiom</a></li></ul>
<ul><li><a href="Axiom_schema" title="Axiom schema">Axiom schema</a>
<ul><li><a href="Axiom_schema_of_replacement" title="Axiom schema of replacement">replacement</a></li>
<li><a href="Axiom_schema_of_specification" title="Axiom schema of specification">specification</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Set_(mathematics)#Basic_operations" title="Set (mathematics)">Operations</a></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="Cartesian_product" title="Cartesian product">Cartesian product</a></li>
<li><a href="Complement_(set_theory)" title="Complement (set theory)">Complement</a> (i.e. set difference)</li>
<li><a href="De_Morgan's_laws" title="De Morgan's laws">De Morgan's laws</a></li>
<li><a href="Disjoint_union" title="Disjoint union">Disjoint union</a></li>
<li><a href="List_of_set_identities_and_relations" title="List of set identities and relations">Identities</a></li>
<li><a href="Intersection_(set_theory)" title="Intersection (set theory)">Intersection</a></li>
<li><a href="Power_set" title="Power set">Power set</a></li>
<li><a href="Symmetric_difference" title="Symmetric difference">Symmetric difference</a></li>
<li><a href="Union_(set_theory)" title="Union (set theory)">Union</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div class="hlist"><ul><li>Concepts</li><li>Methods</li></ul></div></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="Almost" title="Almost">Almost</a></li>
<li><a href="Cardinality" title="Cardinality">Cardinality</a></li>
<li><a href="Cardinal_number" title="Cardinal number">Cardinal number</a>&nbsp;(<a href="Large_cardinal" title="Large cardinal">large</a>)</li>
<li><a href="Class_(set_theory)" title="Class (set theory)">Class</a></li>
<li><a href="Constructible_universe" title="Constructible universe">Constructible universe</a></li>
<li><a href="Continuum_hypothesis" title="Continuum hypothesis">Continuum hypothesis</a></li>
<li><a href="Cantor's_diagonal_argument" title="Cantor's diagonal argument">Diagonal argument</a></li>
<li><a href="Element_(mathematics)" title="Element (mathematics)">Element</a>
<ul><li><a href="Ordered_pair" title="Ordered pair">ordered pair</a></li>
<li><a href="Tuple" title="Tuple">tuple</a></li></ul></li>
<li><a href="Family_of_sets" title="Family of sets">Family</a></li>
<li><a href="Forcing_(mathematics)" title="Forcing (mathematics)">Forcing</a></li>
<li><a href="Bijection" title="Bijection">One-to-one correspondence</a></li>
<li><a href="Ordinal_number" title="Ordinal number">Ordinal number</a></li>

<li><a href="Transfinite_induction" title="Transfinite induction">Transfinite induction</a></li>
<li><a href="Venn_diagram" title="Venn diagram">Venn diagram</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Set_(mathematics)" title="Set (mathematics)">Set</a> types</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="Amorphous_set" title="Amorphous set">Amorphous</a></li>
<li><a href="Countable_set" title="Countable set">Countable</a></li>
<li><a href="Empty_set" title="Empty set">Empty</a></li>
<li><a href="Finite_set" title="Finite set">Finite</a>&nbsp;(<a href="Hereditarily_finite_set" title="Hereditarily finite set">hereditarily</a>)</li>
<li><a href="Filter_(set_theory)" title="Filter (set theory)">Filter</a>
<ul><li><a href="Filter_(set_theory)" title="Filter (set theory)">base</a></li>
<li><a href="Filter_(set_theory)#Filters_and_prefilters" title="Filter (set theory)">subbase</a></li>
<li><a href="Ultrafilter_on_a_set" title="Ultrafilter on a set">Ultrafilter</a></li></ul></li>
<li><a href="Fuzzy_set" title="Fuzzy set">Fuzzy</a></li>
<li><a href="Infinite_set" title="Infinite set">Infinite</a> (<a href="Dedekind-infinite_set" title="Dedekind-infinite set">Dedekind-infinite</a>)</li>
<li><a href="Computable_set" title="Computable set">Recursive</a></li>
<li><a href="Singleton_(mathematics)" title="Singleton (mathematics)">Singleton</a></li>
<li><a href="Subset" title="Subset">Subset&nbsp;<b>·</b> Superset</a></li>
<li><a href="Transitive_set" title="Transitive set">Transitive</a></li>
<li><a href="Uncountable_set" title="Uncountable set">Uncountable</a></li>
<li><a href="Universal_set" title="Universal set">Universal</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Theories</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="Alternative_set_theory" class="mw-redirect" title="Alternative set theory">Alternative</a></li>
<li><a href="Set_theory#Formalized_set_theory" title="Set theory">Axiomatic</a></li>
<li><a href="Naive_set_theory" title="Naive set theory">Naive</a></li>
<li><a href="Cantor's_theorem" title="Cantor's theorem">Cantor's theorem</a></li></ul>
<ul><li><a href="Zermelo_set_theory" title="Zermelo set theory">Zermelo</a>
<ul><li><a href="General_set_theory" title="General set theory">General</a></li></ul></li>
<li><i><a href="Principia_Mathematica" title="Principia Mathematica">Principia Mathematica</a></i>
<ul><li><a href="New_Foundations" title="New Foundations">New Foundations</a></li></ul></li>
<li><a href="Zermelo%E2%80%93Fraenkel_set_theory" title="Zermelo–Fraenkel set theory">Zermelo–Fraenkel </a>
<ul><li><a href="Von_Neumann%E2%80%93Bernays%E2%80%93G%C3%B6del_set_theory" title="Von Neumann–Bernays–Gödel set theory">von Neumann–Bernays–Gödel </a>
<ul><li><a href="Morse%E2%80%93Kelley_set_theory" title="Morse–Kelley set theory">Morse–Kelley</a></li></ul></li>
<li><a href="Kripke%E2%80%93Platek_set_theory" title="Kripke–Platek set theory">Kripke–Platek</a></li>
<li><a href="Tarski%E2%80%93Grothendieck_set_theory" title="Tarski–Grothendieck set theory">Tarski–Grothendieck</a></li></ul></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><div class="hlist"><ul><li><a href="Paradoxes_of_set_theory" title="Paradoxes of set theory">Paradoxes</a></li><li>Problems</li></ul></div></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="Russell's_paradox" title="Russell's paradox">Russell's paradox</a></li>
<li><a href="Suslin's_problem" title="Suslin's problem">Suslin's problem</a></li>
<li><a href="Burali-Forti_paradox" title="Burali-Forti paradox">Burali-Forti paradox</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Set theorists</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="Paul_Bernays" title="Paul Bernays">Paul Bernays</a></li>
<li><a href="Georg_Cantor" title="Georg Cantor">Georg Cantor</a></li>
<li><a href="Paul_Cohen" title="Paul Cohen">Paul Cohen</a></li>
<li><a href="Richard_Dedekind" title="Richard Dedekind">Richard Dedekind</a></li>
<li><a href="Abraham_Fraenkel" title="Abraham Fraenkel">Abraham Fraenkel</a></li>
<li><a href="Kurt_G%C3%B6del" title="Kurt Gödel">Kurt Gödel</a></li>
<li><a href="Thomas_Jech" title="Thomas Jech">Thomas Jech</a></li>
<li><a href="John_von_Neumann" title="John von Neumann">John von Neumann</a></li>
<li><a href="Willard_Van_Orman_Quine" title="Willard Van Orman Quine">Willard Quine</a></li>
<li><a href="Bertrand_Russell" title="Bertrand Russell">Bertrand Russell</a></li>
<li><a href="Thoralf_Skolem" title="Thoralf Skolem">Thoralf Skolem</a></li>
<li><a href="Ernst_Zermelo" title="Ernst Zermelo">Ernst Zermelo</a></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 2025-03-04" href="https://en.wikipedia.org/wiki/?title=Set-builder_notation&amp;oldid=1278820646">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>