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<b>let </b><font color="Maroon">n</font> be   <a href="nat_1.html#NM1">Nat</a>;<br/><b>let </b><font color="Maroon">K</font> be   <a href="vectsp_1.html#NM2">Field</a>;<br/><b>let </b><font color="Maroon">M4</font> be   <a href="matrix_1.html#NM5">Matrix</a> of <font color="Maroon">n</font>,<font color="Maroon">K</font>;<br/><b>let </b><font color="Maroon">M2</font> be   <a href="matrix_1.html#NM5">Matrix</a> of <font color="Maroon">n</font>,<font color="Maroon">K</font>;<br/>







<b>assume </b><a NAME="E1:55"/><i><font color="Green">E36</font></i>: 
<font color="Maroon">M4</font> is <a href="matrix_6.html#V4">Orthogonal</a>
 ;<br/>

<b>take </b>
<font color="Maroon">M4</font>
; <i><font color="Red">:: according to </font></i><a class="ref" href="matrix_8.html#D5" target="_self">MATRIX_8:def 5</a><br/>

<b>thus </b><a NAME="E2:55"/>
( <font color="Maroon">M4</font> is <a href="matrix_6.html#V1">invertible</a> &amp; <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon">M4</font> <a href="matrix_1.html#K5">@</a> </span>)</span> <a href="matrix_6.html#K4">*</a> <font color="Maroon">M2</font></span>)</span> <a href="matrix_6.html#K4">*</a> <font color="Maroon">M4</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon">M4</font> <a href="matrix_6.html#K5">~</a> </span>)</span> <a href="matrix_6.html#K4">*</a> <font color="Maroon">M2</font></span>)</span> <a href="matrix_6.html#K4">*</a> <font color="Maroon">M4</font> )
 <b>by </b><i>, <a class="ref" href="matrix_6.html#D7">MATRIX_6:def 7</a></i>;<br/>


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