@prefix psr: <http://data.loterre.fr/ark:/67375/PSR> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix dc: <http://purl.org/dc/terms/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

psr:-JR0BZJDR-C
  skos:prefLabel "square matrix"@en, "matrice carrée"@fr ;
  a skos:Concept ;
  skos:narrower psr:-B268B0H3-3 .

psr: a skos:ConceptScheme .
psr:-B268B0H3-3
  skos:definition """En algèbre linéaire et multilinéaire, une <b>matrice symétrique</b> est une matrice carrée qui est égale à sa propre transposée, c'est-à-dire telle que <i>a<sub>i,j</sub> = a<sub>j,i</sub></i> pour tous <i>i</i> et <i>j</i> compris entre 1 et <i>n</i>, où les <i>a<sub>i,j</sub></i> sont les coefficients de la matrice et <i>n</i> est son ordre.  
<br/>(Wikipedia, L'Encylopédie Libre, <a href="https://fr.wikipedia.org/wiki/Matrice_sym%C3%A9trique">https://fr.wikipedia.org/wiki/Matrice_sym%C3%A9trique</a>)"""@fr, """In linear algebra, a <b>symmetric matrix</b> is a square matrix that is equal to its transpose. Formally,  <div class="equation-box" style="margin: 0 0 0 1.6em;padding: 6px; border-width:2px; border-style: solid; border-color: #0073CF; background-color: #F5FFFA; text-align: center; display: table"> <span class="mwe-math-element"><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{\\	ext{ is symmetric}}\\\\iff A=A^{\\	extsf {T}}.}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>A</mi>         <mrow class="MJX-TeXAtom-ORD">           <mtext> is symmetric</mtext>         </mrow>         <mspace width="thickmathspace"></mspace>         <mo stretchy="false">⟺<!-- ⟺ --></mo>         <mspace width="thickmathspace"></mspace>         <mi>A</mi>         <mo>=</mo>         <msup>           <mi>A</mi>           <mrow class="MJX-TeXAtom-ORD">             <mrow class="MJX-TeXAtom-ORD">               <mtext mathvariant="sans-serif">T</mtext>             </mrow>           </mrow>         </msup>         <mo>.</mo>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle A{\\	ext{ is symmetric}}\\\\iff A=A^{\\	extsf {T}}.}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/aa1f95691e88a44c37d5f8d3dc50b7143b044076" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:30.491ex; height:3.009ex;" alt="{\\\\displaystyle A{\\	ext{ is symmetric}}\\\\iff A=A^{\\	extsf {T}}.}"></span>  </div> Because equal matrices have equal dimensions, only square matrices can be symmetric. The entries of a symmetric matrix are symmetric with respect to the main diagonal. So if <span class="mwe-math-element"><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_{ij}}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <msub>           <mi>a</mi>           <mrow class="MJX-TeXAtom-ORD">             <mi>i</mi>             <mi>j</mi>           </mrow>         </msub>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle a_{ij}}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ebea6cd2813c330c798921a2894b358f7b643917" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:2.707ex; height:2.343ex;" alt="{\\\\displaystyle a_{ij}}"></span> denotes the entry in the <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\\\\displaystyle i}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>i</mi>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle i}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/add78d8608ad86e54951b8c8bd6c8d8416533d20" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:0.802ex; height:2.176ex;" alt="{\\\\displaystyle i}"></span>th row and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\\\\displaystyle j}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>j</mi>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle j}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2f461e54f5c093e92a55547b9764291390f0b5d0" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -0.671ex; margin-left: -0.027ex; width:0.985ex; height:2.509ex;" alt="{\\\\displaystyle j}"></span>th column then  <div class="equation-box" style="margin: 0 0 0 1.6em;padding: 6px; border-width:2px; border-style: solid; border-color: #0073CF; background-color: #F5FFFA; text-align: center; display: table"> <span class="mwe-math-element"><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{\\	ext{ is symmetric}}\\\\iff {\\	ext{ for every }}i,j,\\\\quad a_{ji}=a_{ij}}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>A</mi>         <mrow class="MJX-TeXAtom-ORD">           <mtext> is symmetric</mtext>         </mrow>         <mspace width="thickmathspace"></mspace>         <mo stretchy="false">⟺<!-- ⟺ --></mo>         <mspace width="thickmathspace"></mspace>         <mrow class="MJX-TeXAtom-ORD">           <mtext> for every </mtext>         </mrow>         <mi>i</mi>         <mo>,</mo>         <mi>j</mi>         <mo>,</mo>         <mspace width="1em"></mspace>         <msub>           <mi>a</mi>           <mrow class="MJX-TeXAtom-ORD">             <mi>j</mi>             <mi>i</mi>           </mrow>         </msub>         <mo>=</mo>         <msub>           <mi>a</mi>           <mrow class="MJX-TeXAtom-ORD">             <mi>i</mi>             <mi>j</mi>           </mrow>         </msub>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle A{\\	ext{ is symmetric}}\\\\iff {\\	ext{ for every }}i,j,\\\\quad a_{ji}=a_{ij}}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2e3f724afb67e8a088490f4bfb8e7df4b7280178" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:46.531ex; height:2.843ex;" alt="{\\\\displaystyle A{\\	ext{ is symmetric}}\\\\iff {\\	ext{ for every }}i,j,\\\\quad a_{ji}=a_{ij}}"></span>  </div> for all indices <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\\\\displaystyle i}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>i</mi>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle i}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/add78d8608ad86e54951b8c8bd6c8d8416533d20" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:0.802ex; height:2.176ex;" alt="{\\\\displaystyle i}"></span> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\\\\displaystyle j.}">   <semantics>     <mrow class="MJX-TeXAtom-ORD">       <mstyle displaystyle="true" scriptlevel="0">         <mi>j</mi>         <mo>.</mo>       </mstyle>     </mrow>     <annotation encoding="application/x-tex">{\\\\displaystyle j.}</annotation>   </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3a24040d2c50c228edf9b031ce3db3d04101cb22" class="mwe-math-fallback-image-inline mw-invert" aria-hidden="true" style="vertical-align: -0.671ex; margin-left: -0.027ex; width:1.632ex; height:2.509ex;" alt="{\\\\displaystyle j.}"></span> Every square diagonal matrix is symmetric, since all off-diagonal elements are zero. Similarly in characteristic different from 2, each diagonal element of a skew-symmetric matrix must be zero, since each is its own negative. In linear algebra, a real symmetric matrix represents a self-adjoint operator represented in an orthonormal basis over a real inner product space. The corresponding object for a complex inner product space is a Hermitian matrix with complex-valued entries, which is equal to its conjugate transpose. Therefore, in linear algebra over the complex numbers, it is often assumed that a symmetric matrix refers to one which has real-valued entries.  Symmetric matrices appear naturally in a variety of applications, and typical numerical linear algebra software makes special accommodations for them.  
<br/>(Wikipedia, The Free Encyclopedia, <a href="https://en.wikipedia.org/wiki/Symmetric_matrix">https://en.wikipedia.org/wiki/Symmetric_matrix</a>)"""@en ;
  skos:exactMatch <https://fr.wikipedia.org/wiki/Matrice_sym%C3%A9trique>, <https://en.wikipedia.org/wiki/Symmetric_matrix> ;
  skos:prefLabel "matrice symétrique"@fr, "symmetric matrix"@en ;
  skos:broader psr:-JR0BZJDR-C ;
  a skos:Concept ;
  skos:inScheme psr: ;
  dc:modified "2024-10-18"^^xsd:date .

