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<h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Maximumsnorm</span></h1>
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<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="de" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="de" dir="ltr"><p>Die <b>Maximumsnorm</b>, <b>Maximumnorm</b> oder <b>Tschebyschew-Norm</b><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> ist eine spezielle <a href="Norm_(Mathematik)" title="Norm (Mathematik)">Norm</a> für Funktionen beziehungsweise für <a href="Vektor" title="Vektor">Vektoren</a> oder <a href="Matrix_(Mathematik)" title="Matrix (Mathematik)">Matrizen</a>. Sie ist ein Spezialfall der <a href="Supremumsnorm" title="Supremumsnorm">Supremumsnorm</a>.
</p>

<div class="mw-heading mw-heading2"><h2 id="Definition">Definition</h2></div>
<p>Sei <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 B}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>B</mi>
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<annotation encoding="application/x-tex">{\displaystyle B}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/47136aad860d145f75f3eed3022df827cee94d7a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle B}" loading="lazy"></span> ein <a href="Kompakter_Raum" title="Kompakter Raum">kompakter Raum</a> und <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 C(B)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>C</mi>
<mo stretchy="false">(</mo>
<mi>B</mi>
<mo stretchy="false">)</mo>
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<annotation encoding="application/x-tex">{\displaystyle C(B)}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0b2a02767cdaf50c796081e028debc06099f24a4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.34ex; height:2.843ex;" alt="{\displaystyle C(B)}" loading="lazy"></span> die Menge aller auf <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 B}">
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<mrow class="MJX-TeXAtom-ORD">
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<mi>B</mi>
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<annotation encoding="application/x-tex">{\displaystyle B}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/47136aad860d145f75f3eed3022df827cee94d7a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle B}" loading="lazy"></span> reell- oder komplexwertigen <a href="Stetige_Funktion" title="Stetige Funktion">stetigen Funktionen</a>. Dann heißt die Funktion <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 \|\cdot \|_{\max }\colon C(B)\to \mathbb {R} }">
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<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
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<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
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<mo movablelimits="true" form="prefix">max</mo>
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<mi>C</mi>
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<annotation encoding="application/x-tex">{\displaystyle \|\cdot \|_{\max }\colon C(B)\to \mathbb {R} }</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c8fc7f80dcd3fc10a56b1b3be15a01816a78093b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.961ex; height:2.843ex;" alt="{\displaystyle \|\cdot \|_{\max }\colon C(B)\to \mathbb {R} }" loading="lazy"></span>, die durch
</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\|_{\max }:=\max _{t\in B}|f(t)|}">
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<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
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<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
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<mo movablelimits="true" form="prefix">max</mo>
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<mo>:=</mo>
<munder>
<mo movablelimits="true" form="prefix">max</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mi>B</mi>
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</munder>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
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<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \|f\|_{\max }:=\max _{t\in B}|f(t)|}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1ba0a166cf28f78b1cd9e2bea58a079d541ece57.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:20.574ex; height:4.176ex;" alt="{\displaystyle \|f\|_{\max }:=\max _{t\in B}|f(t)|}" loading="lazy"></span></dd></dl>
<p>definiert ist, Maximumsnorm. Die Funktion wird auch mit <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 \|\cdot \|_{\infty }}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mo>⋅<!-- ⋅ --></mo>
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<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
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<mi mathvariant="normal">∞<!-- ∞ --></mi>
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<annotation encoding="application/x-tex">{\displaystyle \|\cdot \|_{\infty }}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/b723232adf7317abb1fc1c1326e1e4f79616a7e4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.879ex; height:2.843ex;" alt="{\displaystyle \|\cdot \|_{\infty }}" loading="lazy"></span> bezeichnet und erfüllt die drei charakteristischen Eigenschaften einer <a href="Norm_(Mathematik)" title="Norm (Mathematik)">Norm</a>.<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> Wohldefiniert ist die Maximumsnorm aufgrund des <a href="Satz_vom_Minimum_und_Maximum" title="Satz vom Minimum und Maximum">Satzes vom Minimum und Maximum</a>, der die Existenz des Maximums sichert.
</p>
<div class="mw-heading mw-heading2"><h2 id="Eigenschaften">Eigenschaften</h2></div>
<ul><li>Die Menge der stetigen Funktionen auf einer kompakten Menge <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 C(B)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>C</mi>
<mo stretchy="false">(</mo>
<mi>B</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle C(B)}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0b2a02767cdaf50c796081e028debc06099f24a4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.34ex; height:2.843ex;" alt="{\displaystyle C(B)}" loading="lazy"></span> ist mit der Maximumsnorm ein <a href="Banachraum" title="Banachraum">vollständiger normierter Raum</a>.<sup id="cite_ref-alt38_3-0" class="reference"><a href="#cite_note-alt38-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup></li></ul>
<ul><li>Zusammen mit dem <a href="Produkt_(Mathematik)" title="Produkt (Mathematik)">Produkt</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 (fg)(x):=f(x)g(x)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>f</mi>
<mi>g</mi>
<mo stretchy="false">)</mo>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>:=</mo>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mi>g</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (fg)(x):=f(x)g(x)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f6dcd7c43e0515a4dd60121cfd786dbb304814b9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:19.761ex; height:2.843ex;" alt="{\displaystyle (fg)(x):=f(x)g(x)}" loading="lazy"></span> ist der normierte Raum <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 (C(B),\|\cdot \|_{\text{max}})}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>C</mi>
<mo stretchy="false">(</mo>
<mi>B</mi>
<mo stretchy="false">)</mo>
<mo>,</mo>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mo>⋅<!-- ⋅ --></mo>
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<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mtext>max</mtext>
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</msub>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (C(B),\|\cdot \|_{\text{max}})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/d4664d3bf1345f553f8874b23e2d83268d59a5cc.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:15.478ex; height:2.843ex;" alt="{\displaystyle (C(B),\|\cdot \|_{\text{max}})}" loading="lazy"></span> eine kommutative <a href="Banachalgebra" title="Banachalgebra">Banachalgebra</a>.<sup id="cite_ref-alt38_3-1" class="reference"><a href="#cite_note-alt38-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup></li></ul>
<div class="mw-heading mw-heading2"><h2 id="Spezialfälle"><span id="Spezialf.C3.A4lle"></span>Spezialfälle</h2></div>
<p>Ein wichtiger Spezialfall ist die Maximumsnorm für <a href="Vektor" title="Vektor">Vektoren</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 x\in K^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
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<annotation encoding="application/x-tex">{\displaystyle x\in K^{n}}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/567099788cbfb81999a3af4b8b2f1cfc4922c5d7.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:7.483ex; height:2.343ex;" alt="{\displaystyle x\in K^{n}}" loading="lazy"></span>, wobei <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\in \{\mathbb {R} ,\mathbb {C} \}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>K</mi>
<mo>∈<!-- ∈ --></mo>
<mo fence="false" stretchy="false">{</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
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<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">C</mi>
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<mo fence="false" stretchy="false">}</mo>
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</mrow>
<annotation encoding="application/x-tex">{\displaystyle K\in \{\mathbb {R} ,\mathbb {C} \}}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8b993942178c73543a63922a2c15e1ec8b936a47.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:11.622ex; height:2.843ex;" alt="{\displaystyle K\in \{\mathbb {R} ,\mathbb {C} \}}" loading="lazy"></span>. Wählt man <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 B=\{1,\ldots ,n\}}">
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<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>B</mi>
<mo>=</mo>
<mo fence="false" stretchy="false">{</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>n</mi>
<mo fence="false" stretchy="false">}</mo>
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<annotation encoding="application/x-tex">{\displaystyle B=\{1,\ldots ,n\}}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/46727e5b9564009eefb236e30af009ae0870f89f.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.923ex; height:2.843ex;" alt="{\displaystyle B=\{1,\ldots ,n\}}" loading="lazy"></span> und stattet die Menge mit der <a href="Diskrete_Topologie" title="Diskrete Topologie">diskreten Topologie</a> aus, dann ist <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 B}">
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<mrow class="MJX-TeXAtom-ORD">
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<mi>B</mi>
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<annotation encoding="application/x-tex">{\displaystyle B}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/47136aad860d145f75f3eed3022df827cee94d7a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle B}" loading="lazy"></span> ein kompakter Raum und jede reell- oder komplexwertige Funktion auf <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 B}">
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<mrow class="MJX-TeXAtom-ORD">
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<mi>B</mi>
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<annotation encoding="application/x-tex">{\displaystyle B}</annotation>
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</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/47136aad860d145f75f3eed3022df827cee94d7a.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.764ex; height:2.176ex;" alt="{\displaystyle B}" loading="lazy"></span> ist <a href="Stetige_Funktion" title="Stetige Funktion">stetig</a>. Somit entspricht der Raum <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 C(\{1,\ldots ,n\})}">
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<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>C</mi>
<mo stretchy="false">(</mo>
<mo fence="false" stretchy="false">{</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>n</mi>
<mo fence="false" stretchy="false">}</mo>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle C(\{1,\ldots ,n\})}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/9f60b2670bb02555a0cbd1492911caf6257be871.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:13.636ex; height:2.843ex;" alt="{\displaystyle C(\{1,\ldots ,n\})}" loading="lazy"></span> dem <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>n</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle n}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a601995d55609f2d9f5e233e36fbe9ea26011b3b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.395ex; height:1.676ex;" alt="{\displaystyle n}" loading="lazy"></span>-dimensionalen Vektorraum <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^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle K^{n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1d63366b3d00300e06eee81786182062b98775c5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.312ex; height:2.343ex;" alt="{\displaystyle K^{n}}" loading="lazy"></span> und die Maximumsnorm auf Vektoren ist ein Spezialfall der Maximumsnorm für stetige Funktionen auf kompakten Mengen. Sieht man eine <a href="Matrix_(Mathematik)" title="Matrix (Mathematik)">Matrix</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 A\in K^{m\times n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>A</mi>
<mo>∈<!-- ∈ --></mo>
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>×<!-- × --></mo>
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle A\in K^{m\times n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ab303433d6aa889f1f94258f6afb6a04ffea388d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:10.617ex; height:2.343ex;" alt="{\displaystyle A\in K^{m\times n}}" loading="lazy"></span> als entsprechend langen Vektor im <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^{m\cdot n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>⋅<!-- ⋅ --></mo>
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle K^{m\cdot n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ecc3750b623c287872df31cf4ccca0589b4054fb.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:5.213ex; height:2.343ex;" alt="{\displaystyle K^{m\cdot n}}" loading="lazy"></span> an, ist es auch möglich, die Maximumsnorm auf Matrizen zu definieren.
</p>
<div class="mw-heading mw-heading3"><h3 id="Als_Vektornorm">Als Vektornorm</h3></div>
<p>Für einen Vektor <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_{1},\ldots ,x_{n})\in K^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>x</mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<msub>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<msub>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
<mo stretchy="false">)</mo>
<mo>∈<!-- ∈ --></mo>
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle x=(x_{1},\ldots ,x_{n})\in K^{n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/d7536639f167b12b45f93637deba1e09cb863a27.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:22.501ex; height:2.843ex;" alt="{\displaystyle x=(x_{1},\ldots ,x_{n})\in K^{n}}" loading="lazy"></span> nennt man
</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\|_{\max }:=\max(|x_{1}|,\ldots ,|x_{n}|)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>x</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
<mo>:=</mo>
<mo movablelimits="true" form="prefix">max</mo>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<msub>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<msub>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \|x\|_{\max }:=\max(|x_{1}|,\ldots ,|x_{n}|)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/2162ad0892929dfed335c5a8607e689b542dcf87.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:29.524ex; height:2.843ex;" alt="{\displaystyle \|x\|_{\max }:=\max(|x_{1}|,\ldots ,|x_{n}|)}" loading="lazy"></span></dd></dl>
<p>die <i>Maximumsnorm</i> von <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>x</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle x}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/87f9e315fd7e2ba406057a97300593c4802b53e4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.33ex; height:1.676ex;" alt="{\displaystyle x}" loading="lazy"></span>.<sup id="cite_ref-Heuser2002_4-0" class="reference"><a href="#cite_note-Heuser2002-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
Die Maximumsnorm kann auch als Grenzfall der <a href="P-Norm" title="P-Norm"><i>p</i>-Normen</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 \textstyle \|x\|_{p}:=(\sum _{i=1}^{n}|x_{i}|^{p})^{1/p}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mstyle displaystyle="false" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>x</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>p</mi>
</mrow>
</msub>
<mo>:=</mo>
<mo stretchy="false">(</mo>
<munderover>
<mo>∑<!-- ∑ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</munderover>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<msub>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
</mrow>
</msub>
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>p</mi>
</mrow>
</msup>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mn>1</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mi>p</mi>
</mrow>
</msup>
</mstyle>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \textstyle \|x\|_{p}:=(\sum _{i=1}^{n}|x_{i}|^{p})^{1/p}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/36158c035f8a3d522c9ced06c3d7e7b734035a34.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:23.195ex; height:3.343ex;" alt="{\displaystyle \textstyle \|x\|_{p}:=(\sum _{i=1}^{n}|x_{i}|^{p})^{1/p}}" loading="lazy"></span> aufgefasst werden. Lässt man <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>p</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle p}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/81eac1e205430d1f40810df36a0edffdc367af36.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; margin-left: -0.089ex; width:1.259ex; height:2.009ex;" alt="{\displaystyle p}" loading="lazy"></span> gegen unendlich laufen, so erhält man aus der <i>p</i>-Norm die Maximumsnorm.<sup id="cite_ref-Heuser2002_4-1" class="reference"><a href="#cite_note-Heuser2002-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Aus diesem Grund wird die Maximumsnorm für Vektoren auch als <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 \infty }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi mathvariant="normal">∞<!-- ∞ --></mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \infty }</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c26c105004f30c27aa7c2a9c601550a4183b1f21.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.324ex; height:1.676ex;" alt="{\displaystyle \infty }" loading="lazy"></span>-<i>Norm (Unendlich-Norm)</i> bezeichnet.
</p><p>Die <a href="Norm_(Mathematik)#Normkugeln" title="Norm (Mathematik)">Kugeln</a> bezüglich der Maximumsnorm sind gerade die <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>n</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle n}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a601995d55609f2d9f5e233e36fbe9ea26011b3b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.395ex; height:1.676ex;" alt="{\displaystyle n}" loading="lazy"></span>-dimensionalen <a href="Hyperw%C3%BCrfel" title="Hyperwürfel">Würfel</a>, deren Kanten alle parallel zu den Koordinatenachsen verlaufen.<br>
Die <a href="Extremalpunkt" title="Extremalpunkt">Extremalpunkte</a> einer solchen abgeschlossenen „Kugel“ sind gerade die Eckpunkte dieses Würfels. Die Menge dieser Punkte ist (für <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>1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>n</mi>
<mo>&gt;</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle n&gt;1}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ee74e1cc07e7041edf0fcbd4481f5cd32ad17b64.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:5.656ex; height:2.176ex;" alt="{\displaystyle n>1}" loading="lazy"></span>) eine echte Teilmenge des Randes des Würfels, der aus allen Rand-(Hyper-)Flächen des Würfels besteht. <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^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle K^{n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1d63366b3d00300e06eee81786182062b98775c5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.312ex; height:2.343ex;" alt="{\displaystyle K^{n}}" loading="lazy"></span> mit der Maximumsnorm ist für <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>1}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>n</mi>
<mo>&gt;</mo>
<mn>1</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle n&gt;1}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ee74e1cc07e7041edf0fcbd4481f5cd32ad17b64.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:5.656ex; height:2.176ex;" alt="{\displaystyle n>1}" loading="lazy"></span> also ein nicht <a href="Strikt_konvexer_Raum" title="Strikt konvexer Raum">strikt konvexer Raum</a>. Trotzdem ist die Maximumsnorm <a href="%C3%84quivalente_Normen" title="Äquivalente Normen">äquivalent</a> zur <a href="Euklidische_Norm" title="Euklidische Norm">Euklidischen Norm</a>, durch die <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^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle K^{n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1d63366b3d00300e06eee81786182062b98775c5.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.312ex; height:2.343ex;" alt="{\displaystyle K^{n}}" loading="lazy"></span> strikt konvex wird.
</p>
<div class="mw-heading mw-heading3"><h3 id="Als_Matrixnorm">Als Matrixnorm</h3></div>
<p>Analog zur <a href="Vektornorm" class="mw-redirect" title="Vektornorm">Vektornorm</a> hat die Maximumsnorm für Matrizen <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=(a_{ij})_{i,j}\in K^{m\times n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>A</mi>
<mo>=</mo>
<mo stretchy="false">(</mo>
<msub>
<mi>a</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mi>j</mi>
</mrow>
</msub>
<msub>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
</mrow>
</msub>
<mo>∈<!-- ∈ --></mo>
<msup>
<mi>K</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>m</mi>
<mo>×<!-- × --></mo>
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle A=(a_{ij})_{i,j}\in K^{m\times n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/7f6725a840bc84b169a323d6a82ca9fd34ac7d75.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:20.167ex; height:3.009ex;" alt="{\displaystyle A=(a_{ij})_{i,j}\in K^{m\times n}}" loading="lazy"></span> die Darstellung
</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 \|A\|_{\max }:=\max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>A</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
<mo>:=</mo>
<munder>
<mo movablelimits="true" form="prefix">max</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac linethickness="0">
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>m</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>n</mi>
</mrow>
</mfrac>
</mrow>
</munder>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<msub>
<mi>a</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mi>j</mi>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \|A\|_{\max }:=\max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/0e761c506862e8b072aa323f202f407e42071717.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.671ex; width:21.693ex; height:5.676ex;" alt="{\displaystyle \|A\|_{\max }:=\max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}" loading="lazy"></span>.</dd></dl>
<p>Diese Norm ist jedoch nicht <a href="Submultiplikativit%C3%A4t" title="Submultiplikativität">submultiplikativ</a>, daher wird im Zusammenhang mit Matrizen statt dieser Norm oftmals die submultiplikative <a href="Gesamtnorm" title="Gesamtnorm">Gesamtnorm</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 \textstyle \|A\|_{G}:={\sqrt {mn}}\cdot \max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mstyle displaystyle="false" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>A</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>G</mi>
</mrow>
</msub>
<mo>:=</mo>
<mrow class="MJX-TeXAtom-ORD">
<msqrt>
<mi>m</mi>
<mi>n</mi>
</msqrt>
</mrow>
<mo>⋅<!-- ⋅ --></mo>
<munder>
<mo movablelimits="true" form="prefix">max</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac linethickness="0">
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>m</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>j</mi>
<mo>=</mo>
<mn>1</mn>
<mo>,</mo>
<mo>…<!-- … --></mo>
<mo>,</mo>
<mi>n</mi>
</mrow>
</mfrac>
</mrow>
</munder>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<msub>
<mi>a</mi>
<mrow class="MJX-TeXAtom-ORD">
<mi>i</mi>
<mi>j</mi>
</mrow>
</msub>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
</mstyle>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \textstyle \|A\|_{G}:={\sqrt {mn}}\cdot \max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c30cfab240f949b2f4f13bcf94d4d66a42e27cdd.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:31.534ex; height:4.176ex;" alt="{\displaystyle \textstyle \|A\|_{G}:={\sqrt {mn}}\cdot \max _{{i=1,\ldots ,m} \atop {j=1,\ldots ,n}}|a_{ij}|}" loading="lazy"></span> verwendet.
</p>
<div class="mw-heading mw-heading2"><h2 id="Beispiele">Beispiele</h2></div>
<dl><dt>Spaltenvektor</dt></dl>
<p>Für den <a href="Matrix_(Mathematik)" title="Matrix (Mathematik)">Spaltenvektor</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 (-5,7,4,-9)^{T}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mn>5</mn>
<mo>,</mo>
<mn>7</mn>
<mo>,</mo>
<mn>4</mn>
<mo>,</mo>
<mo>−<!-- − --></mo>
<mn>9</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>T</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (-5,7,4,-9)^{T}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1f62ce14b2a8595e9de935fe6b4df310e3ab1ff9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.566ex; height:3.176ex;" alt="{\displaystyle (-5,7,4,-9)^{T}}" loading="lazy"></span> gilt
</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 \left\|{\begin{pmatrix}-5\\7\\4\\-9\end{pmatrix}}\right\|_{\max }=\max(|-5|,|7|,|4|,|-9|)=9\,.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msub>
<mrow>
<mo symmetric="true">‖</mo>
<mrow class="MJX-TeXAtom-ORD">
<mrow>
<mo>(</mo>
<mtable rowspacing="4pt" columnspacing="1em">
<mtr>
<mtd>
<mo>−<!-- − --></mo>
<mn>5</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mn>7</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mn>4</mn>
</mtd>
</mtr>
<mtr>
<mtd>
<mo>−<!-- − --></mo>
<mn>9</mn>
</mtd>
</mtr>
</mtable>
<mo>)</mo>
</mrow>
</mrow>
<mo symmetric="true">‖</mo>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
<mo>=</mo>
<mo movablelimits="true" form="prefix">max</mo>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>−<!-- − --></mo>
<mn>5</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mn>7</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mn>4</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>−<!-- − --></mo>
<mn>9</mn>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mn>9</mn>
<mspace width="thinmathspace"></mspace>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \left\|{\begin{pmatrix}-5\\7\\4\\-9\end{pmatrix}}\right\|_{\max }=\max(|-5|,|7|,|4|,|-9|)=9\,.}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/ca7051ecdc74f4d4f9c2f5f7fc3aa315f8905561.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -5.838ex; width:46.541ex; height:12.676ex;" alt="{\displaystyle \left\|{\begin{pmatrix}-5\\7\\4\\-9\end{pmatrix}}\right\|_{\max }=\max(|-5|,|7|,|4|,|-9|)=9\,.}" loading="lazy"></span></dd></dl>
<p>Die Maximumsnorm von <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 (-5,7,4,-9)^{T}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mo>−<!-- − --></mo>
<mn>5</mn>
<mo>,</mo>
<mn>7</mn>
<mo>,</mo>
<mn>4</mn>
<mo>,</mo>
<mo>−<!-- − --></mo>
<mn>9</mn>
<msup>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>T</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (-5,7,4,-9)^{T}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/1f62ce14b2a8595e9de935fe6b4df310e3ab1ff9.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.566ex; height:3.176ex;" alt="{\displaystyle (-5,7,4,-9)^{T}}" loading="lazy"></span> ist also 9.
</p>
<dl><dt>Funktion</dt></dl>
<p>Für die <a href="Gebrochenrationale_Funktion" class="mw-redirect" title="Gebrochenrationale Funktion">gebrochenrationale Funktion</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 f\colon [-2,2]\to \mathbb {R} }">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>f</mi>
<mo>:<!-- : --></mo>
<mo stretchy="false">[</mo>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mo>,</mo>
<mn>2</mn>
<mo stretchy="false">]</mo>
<mo stretchy="false">→<!-- → --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle f\colon [-2,2]\to \mathbb {R} }</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/d4f612ad012ef44637bd7b6f443181034605a128.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.065ex; height:2.843ex;" alt="{\displaystyle f\colon [-2,2]\to \mathbb {R} }" loading="lazy"></span> definiert durch <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)=1000(x^{2}-6)/(x^{3}-6000)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mn>1000</mn>
<mo stretchy="false">(</mo>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>6</mn>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo>/</mo>
</mrow>
<mo stretchy="false">(</mo>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>6000</mn>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle f(x)=1000(x^{2}-6)/(x^{3}-6000)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/8ea11beb8c4288961931a6250eaa1e5c5f51bd8c.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:33.208ex; height:3.176ex;" alt="{\displaystyle f(x)=1000(x^{2}-6)/(x^{3}-6000)}" loading="lazy"></span> gilt
</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\|_{\max }=\max _{x\in [-2,2]}\left(1000\left|{\frac {x^{2}-6}{x^{3}-6000}}\right|\right)=1\,.}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>f</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
<mo>=</mo>
<munder>
<mo movablelimits="true" form="prefix">max</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>x</mi>
<mo>∈<!-- ∈ --></mo>
<mo stretchy="false">[</mo>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mo>,</mo>
<mn>2</mn>
<mo stretchy="false">]</mo>
</mrow>
</munder>
<mrow>
<mo>(</mo>
<mrow>
<mn>1000</mn>
<mrow>
<mo>|</mo>
<mrow class="MJX-TeXAtom-ORD">
<mfrac>
<mrow>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>2</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>6</mn>
</mrow>
<mrow>
<msup>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mn>3</mn>
</mrow>
</msup>
<mo>−<!-- − --></mo>
<mn>6000</mn>
</mrow>
</mfrac>
</mrow>
<mo>|</mo>
</mrow>
</mrow>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mn>1</mn>
<mspace width="thinmathspace"></mspace>
<mo>.</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \|f\|_{\max }=\max _{x\in [-2,2]}\left(1000\left|{\frac {x^{2}-6}{x^{3}-6000}}\right|\right)=1\,.}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/84ca5b6089caa7cd6d16ef0a95478f88f8f1884b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:42.468ex; height:6.509ex;" alt="{\displaystyle \|f\|_{\max }=\max _{x\in [-2,2]}\left(1000\left|{\frac {x^{2}-6}{x^{3}-6000}}\right|\right)=1\,.}" loading="lazy"></span></dd></dl>
<p>Dies kann durch zweifache <a href="Differentialrechnung" title="Differentialrechnung">Ableitung</a> und Bestimmung der <a href="Extremwert" title="Extremwert">Extremwerte</a> gezeigt werden. Die Maximumsnorm der Funktion <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>f</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle f}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/132e57acb643253e7810ee9702d9581f159a1c61.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.279ex; height:2.509ex;" alt="{\displaystyle f}" loading="lazy"></span> auf dem Intervall <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 [-2,2]}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">[</mo>
<mo>−<!-- − --></mo>
<mn>2</mn>
<mo>,</mo>
<mn>2</mn>
<mo stretchy="false">]</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle [-2,2]}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f94b820404eca2a458cb2c7d8c24be85fffccf90.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:6.461ex; height:2.843ex;" alt="{\displaystyle [-2,2]}" loading="lazy"></span> ist also 1.
</p>
<div class="mw-heading mw-heading2"><h2 id="Supremumsnorm">Supremumsnorm</h2></div>
<div class="hauptartikel" role="navigation"><span class="hauptartikel-pfeil" title="siehe" aria-hidden="true" role="presentation">→&nbsp;</span><i><span class="hauptartikel-text">Hauptartikel</span>: <a href="Supremumsnorm" title="Supremumsnorm">Supremumsnorm</a></i></div>
<p>Im Gegensatz zur Maximumsnorm wird die Supremumsnorm <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 \textstyle \|f\|_{\sup }:=\sup _{t\in X}|f(t)|}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mstyle displaystyle="false" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mi>f</mi>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">sup</mo>
</mrow>
</msub>
<mo>:=</mo>
<munder>
<mo movablelimits="true" form="prefix">sup</mo>
<mrow class="MJX-TeXAtom-ORD">
<mi>t</mi>
<mo>∈<!-- ∈ --></mo>
<mi>X</mi>
</mrow>
</munder>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>f</mi>
<mo stretchy="false">(</mo>
<mi>t</mi>
<mo stretchy="false">)</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
</mstyle>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \textstyle \|f\|_{\sup }:=\sup _{t\in X}|f(t)|}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/425a412c08c23052d04129aaf1969157df0b0391.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:22.489ex; height:3.009ex;" alt="{\displaystyle \textstyle \|f\|_{\sup }:=\sup _{t\in X}|f(t)|}" loading="lazy"></span> nicht für stetige, sondern für beschränkte Funktionen <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>f</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle f}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/132e57acb643253e7810ee9702d9581f159a1c61.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.279ex; height:2.509ex;" alt="{\displaystyle f}" loading="lazy"></span> definiert. In diesem Fall ist es nicht notwendig, dass <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>X</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle X}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/68baa052181f707c662844a465bfeeb135e82bab.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.98ex; height:2.176ex;" alt="{\displaystyle X}" loading="lazy"></span> kompakt ist; <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>X</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle X}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/68baa052181f707c662844a465bfeeb135e82bab.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.98ex; height:2.176ex;" alt="{\displaystyle X}" loading="lazy"></span> kann eine beliebige Menge sein. Da stetige Funktionen auf kompakten Räumen beschränkt sind, ist die Maximumsnorm ein Spezialfall der Supremumsnorm.
</p>
<div class="mw-heading mw-heading2"><h2 id="Veranschaulichung">Veranschaulichung</h2></div>
<p>Anschaulich gesprochen ist der aus der Maximumsnorm abgeleitete Abstand immer dann relevant, wenn man sich in einem mehrdimensionalen Raum in alle Dimensionen gleichzeitig und unabhängig voneinander gleich schnell bewegen kann.
</p><p>Als einfaches Beispiel hierfür kann die Bewegung eines <a href="K%C3%B6nig_(Schach)" title="König (Schach)">Königs</a> auf einem <a href="Schachbrett" title="Schachbrett">Schachbrett</a> dienen: Gemäß den Regeln kann sich der König in einem Zug auf eine benachbarte Linie oder eine benachbarte Reihe bewegen, wobei beides kombiniert werden kann (Diagonalzug). Um nun zu bestimmen, wie viele Züge ein König minimal benötigt, um von einem Feld auf ein anderes zu gelangen, muss man das Maximum der durchzuführenden Reihenwechsel und der durchzuführenden Linienwechsel bestimmen. Repräsentiert man also ein Feld durch ein <a href="Geordnetes_Paar" title="Geordnetes Paar">geordnetes Paar</a> der Zahlen 1, …, 8, so benötigt man vom Feld <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,b)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (a,b)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/d7e5710198f33b00695903460983021e75860e2c.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.071ex; height:2.843ex;" alt="{\displaystyle (a,b)}" loading="lazy"></span> zum Feld <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)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (x,y)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/41cf50e4a314ca8e2c30964baa8d26e5be7a9386.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.328ex; height:2.843ex;" alt="{\displaystyle (x,y)}" loading="lazy"></span> gerade
</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 \max(|a-x|,|b-y|)=\|(a,b)-(x,y)\|_{\max }}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo movablelimits="true" form="prefix">max</mo>
<mo stretchy="false">(</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>a</mi>
<mo>−<!-- − --></mo>
<mi>x</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo>,</mo>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mi>b</mi>
<mo>−<!-- − --></mo>
<mi>y</mi>
<mrow class="MJX-TeXAtom-ORD">
<mo stretchy="false">|</mo>
</mrow>
<mo stretchy="false">)</mo>
<mo>=</mo>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mo stretchy="false">(</mo>
<mi>a</mi>
<mo>,</mo>
<mi>b</mi>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mo stretchy="false">(</mo>
<mi>x</mi>
<mo>,</mo>
<mi>y</mi>
<mo stretchy="false">)</mo>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \max(|a-x|,|b-y|)=\|(a,b)-(x,y)\|_{\max }}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/5cd8b07a68fd3304205f9643e067c7ff31b310d3.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:42.104ex; height:2.843ex;" alt="{\displaystyle \max(|a-x|,|b-y|)=\|(a,b)-(x,y)\|_{\max }}" loading="lazy"></span> Züge.</dd></dl>
<p>Beispiel: Die Felder b8 und f3 des Schachbretts werden in dieser Notation durch die Paare <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 (2,8)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mn>2</mn>
<mo>,</mo>
<mn>8</mn>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (2,8)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/02acdb61f21921e43e544989f0e0423fc6c7d2fa.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.168ex; height:2.843ex;" alt="{\displaystyle (2,8)}" loading="lazy"></span> und <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 (6,3)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo stretchy="false">(</mo>
<mn>6</mn>
<mo>,</mo>
<mn>3</mn>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle (6,3)}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/f272cdd319109f701788528a8e25e04f5ae2cee0.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:5.168ex; height:2.843ex;" alt="{\displaystyle (6,3)}" loading="lazy"></span> dargestellt. Ein König benötigt also <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 \|(2,8)-(6,3)\|_{\max }=5}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mo stretchy="false">(</mo>
<mn>2</mn>
<mo>,</mo>
<mn>8</mn>
<mo stretchy="false">)</mo>
<mo>−<!-- − --></mo>
<mo stretchy="false">(</mo>
<mn>6</mn>
<mo>,</mo>
<mn>3</mn>
<mo stretchy="false">)</mo>
<msub>
<mo fence="false" stretchy="false">‖<!-- ‖ --></mo>
<mrow class="MJX-TeXAtom-ORD">
<mo movablelimits="true" form="prefix">max</mo>
</mrow>
</msub>
<mo>=</mo>
<mn>5</mn>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \|(2,8)-(6,3)\|_{\max }=5}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/5e0defbff7101f0cb01957f35614ab9f7f40e32c.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:23.054ex; height:2.843ex;" alt="{\displaystyle \|(2,8)-(6,3)\|_{\max }=5}" loading="lazy"></span> Züge, um von einem Feld zum anderen zu gelangen. Dabei wurde nicht berücksichtigt, dass der Weg durch eigene oder gegnerische Figuren versperrt sein kann.
</p><p>Allgemeiner kann die Maximumsnorm benutzt werden, um zu bestimmen, wie schnell man sich in einem zwei- oder dreidimensionalen Raum bewegen kann, wenn angenommen wird, dass die Bewegungen in <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle x}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>x</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle x}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/87f9e315fd7e2ba406057a97300593c4802b53e4.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.33ex; height:1.676ex;" alt="{\displaystyle x}" loading="lazy"></span>-, <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 y}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>y</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle y}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/b8a6208ec717213d4317e666f1ae872e00620a0d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.155ex; height:2.009ex;" alt="{\displaystyle y}" loading="lazy"></span>- (und <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle z}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>z</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle z}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/bf368e72c009decd9b6686ee84a375632e11de98.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.088ex; height:1.676ex;" alt="{\displaystyle z}" loading="lazy"></span>-)Richtung unabhängig, gleichzeitig und mit gleicher Geschwindigkeit erfolgen.
</p><p>Noch allgemeiner kann man ein System betrachten, dessen Zustand durch <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}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>n</mi>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle n}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/a601995d55609f2d9f5e233e36fbe9ea26011b3b.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.395ex; height:1.676ex;" alt="{\displaystyle n}" loading="lazy"></span> unabhängige Parameter bestimmt wird. An allen Parametern können gleichzeitig und ohne gegenseitige Beeinflussung Änderungen vorgenommen werden. Dann „misst“ die Maximumsnorm in <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathbb {R} ^{n}}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<msup>
<mrow class="MJX-TeXAtom-ORD">
<mi mathvariant="double-struck">R</mi>
</mrow>
<mrow class="MJX-TeXAtom-ORD">
<mi>n</mi>
</mrow>
</msup>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle \mathbb {R} ^{n}}</annotation>
</semantics>
</math></span><img src="./_assets_/eb734a37dd21ce173a46342d1cc64c92/c510b63578322050121fe966f2e5770bea43308d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.897ex; height:2.343ex;" alt="{\displaystyle \mathbb {R} ^{n}}" loading="lazy"></span> die Zeit, die man benötigt, um das System von einem Zustand in einen anderen zu überführen. Voraussetzung hierfür ist allerdings, dass man die Parameter so normiert hat, dass gleiche Abstände zwischen den Werten auch gleichen Änderungszeiten entsprechen. Andernfalls müsste man eine gewichtete Version der Maximumsnorm verwenden, die die unterschiedlichen Änderungsgeschwindigkeiten der Parameter berücksichtigt.
</p>
<div class="mw-heading mw-heading2"><h2 id="Einzelnachweise">Einzelnachweise</h2></div>
<ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><a href="#cite_ref-1">↑</a></span> <span class="reference-text"><cite style="font-style:italic">Tschebyschew-Norm</cite>. In: Guido Walz (Hrsg.): <cite style="font-style:italic">Lexikon der Mathematik</cite>. 1. Auflage. Spektrum Akademischer Verlag, Mannheim/Heidelberg 2000, ISBN 978-3-8274-0439-8.<span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rfr_id=info:sid/de.wikipedia.org:Maximumsnorm&amp;rft.atitle=Tschebyschew-Norm&amp;rft.btitle=Lexikon+der+Mathematik&amp;rft.date=2000&amp;rft.edition=1&amp;rft.genre=book&amp;rft.isbn=9783827404398&amp;rft.place=Mannheim%2FHeidelberg&amp;rft.pub=Spektrum+Akademischer+Verlag" style="display:none">&nbsp;</span></span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><a href="#cite_ref-2">↑</a></span> <span class="reference-text"><cite style="font-style:italic">Maximumnorm</cite>. In: Guido Walz (Hrsg.): <cite style="font-style:italic">Lexikon der Mathematik</cite>. 1. Auflage. Spektrum Akademischer Verlag, Mannheim/Heidelberg 2000, ISBN 978-3-8274-0439-8.<span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rfr_id=info:sid/de.wikipedia.org:Maximumsnorm&amp;rft.atitle=Maximumnorm&amp;rft.btitle=Lexikon+der+Mathematik&amp;rft.date=2000&amp;rft.edition=1&amp;rft.genre=book&amp;rft.isbn=9783827404398&amp;rft.place=Mannheim%2FHeidelberg&amp;rft.pub=Spektrum+Akademischer+Verlag" style="display:none">&nbsp;</span></span>
</li>
<li id="cite_note-alt38-3"><span class="mw-cite-backlink">↑ <sup><a href="#cite_ref-alt38_3-0">a</a></sup> <sup><a href="#cite_ref-alt38_3-1">b</a></sup></span> <span class="reference-text">Alt: <cite style="font-style:italic">Lineare Funktionalanalysis</cite>. 5. Auflage. Springer, 2006, ISBN 3-540-34187-0, <span style="white-space:nowrap">S.<span style="display:inline-block;width:.2em">&nbsp;</span>38</span>.<span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rfr_id=info:sid/de.wikipedia.org:Maximumsnorm&amp;rft.au=Alt&amp;rft.btitle=Lineare+Funktionalanalysis&amp;rft.date=2006&amp;rft.edition=5.&amp;rft.genre=book&amp;rft.isbn=3540341870&amp;rft.pages=38&amp;rft.pub=Springer" style="display:none">&nbsp;</span></span>
</li>
<li id="cite_note-Heuser2002-4"><span class="mw-cite-backlink">↑ <sup><a href="#cite_ref-Heuser2002_4-0">a</a></sup> <sup><a href="#cite_ref-Heuser2002_4-1">b</a></sup></span> <span class="reference-text">Harro Heuser: <i>Lehrbuch der Analysis. Teil 2.</i> 14. Auflage Teubner Verlag, 2008, ISBN 978-3-8351-0208-8, S. 11–12.</span>
</li>
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