<?xml version="1.0"?>
<div class="add">

<span class="kw">let </span><font color="Maroon" title="c1">n</font> be    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of  <a href="numbers.html#K5" title="NUMBERS:func.5">NAT</a> ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide"> for <font color="Olive" title="b1">A</font>, <font color="Olive" title="b2">B</font> being  <a href="matrix_1.html#NM3" title="MATRIX_1:NM.3">Matrix</a> of <font color="Maroon" title="c1">n</font>, <a href="numbers.html#K1" title="NUMBERS:func.1">REAL</a>  holds   <a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <span class="p1">(<span class="default"><font color="Olive" title="b1">A</font> <a href="matrixr2.html#K1" title="MATRIXR2:func.1">*</a> <font color="Olive" title="b2">B</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Olive" title="b1">A</font></span>)</span> <a href="real_1.html#K8" title="REAL_1:func.8">*</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Olive" title="b2">B</font></span>)</span></span><br/>

<span class="kw">set </span><font color="Maroon" title="c2">K</font> =  <a href="vectsp_1.html#K2" title="VECTSP_1:func.2">F_Real</a> ;<br/>
<span class="kw">let </span><font color="Maroon" title="c3">A</font>, <font color="Maroon" title="c4">B</font> be   <a href="matrix_1.html#NM3" title="MATRIX_1:NM.3">Matrix</a> of <font color="Maroon" title="c1">n</font>, <a href="numbers.html#K1" title="NUMBERS:func.1">REAL</a> ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide">  <a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="matrixr2.html#K1" title="MATRIXR2:func.1">*</a> <font color="Maroon" title="c4">B</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c3">A</font></span>)</span> <a href="real_1.html#K8" title="REAL_1:func.8">*</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c4">B</font></span>)</span></span><br/>

<span class="kw">reconsider </span><font color="Maroon" title="c5">Na</font> =  <a href="matrixr2.html#K2" title="MATRIXR2:func.2">MXR2MXF</a> <font color="Maroon" title="c3">A</font>, <font color="Maroon" title="c6">Nb</font> =  <a href="matrixr2.html#K2" title="MATRIXR2:func.2">MXR2MXF</a> <font color="Maroon" title="c4">B</font> as   <a href="matrix_1.html#NM5" title="MATRIX_1:NM.5">Matrix</a> of <font color="Maroon" title="c1">n</font>,<a href="vectsp_1.html#K2" title="VECTSP_1:func.2">F_Real</a>  ;<br/>
 <a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="matrixr2.html#K1" title="MATRIXR2:func.1">*</a> <font color="Maroon" title="c4">B</font></span>)</span> = 
<span class="p1">(<span class="default"><a href="matrix_3.html#K12" title="MATRIX_3:func.12">Det</a> <font color="Maroon" title="c5">Na</font></span>)</span> <a href="group_1.html#K8" title="GROUP_1:func.8">*</a> <span class="p1">(<span class="default"><a href="matrix_3.html#K12" title="MATRIX_3:func.12">Det</a> <font color="Maroon" title="c6">Nb</font></span>)</span>
<span class="kw">by</span> <span class="lab"><a class="ref" href="matrixr2.html#T45" target="_self" title="MATRIXR2:th.45">Th45</a></span>
<br/>.= 
<span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c3">A</font></span>)</span> <a href="real_1.html#K8" title="REAL_1:func.8">*</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c4">B</font></span>)</span>

;<br/>
<span class="kw">hence </span><a NAME="E3:49"/>
 <a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">A</font> <a href="matrixr2.html#K1" title="MATRIXR2:func.1">*</a> <font color="Maroon" title="c4">B</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c3">A</font></span>)</span> <a href="real_1.html#K8" title="REAL_1:func.8">*</a> <span class="p1">(<span class="default"><a href="matrixr2.html#K3" title="MATRIXR2:func.3">Det</a> <font color="Maroon" title="c4">B</font></span>)</span>
 ; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide"> verum</span><br/>


</div>
