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<b>let </b><font color="Maroon">n</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> ;<br/><b>let </b><font color="Maroon">x</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="euclid.html#K1">REAL</a> <font color="Maroon">n</font>, <font color="Maroon">y</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="euclid.html#K1">REAL</a> <font color="Maroon">n</font>;<br/>



<a NAME="E1:47"/>
(  <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">x</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">n</font> &amp;  <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">y</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">n</font> )
 
<b>by </b><i/>;<br/>
<a NAME="E2:47"/><b>then </b>
 <a href="complex1.html#K18">abs</a> <span class="p1"><a href="euclid_2.html#K1">|(</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">x</font></span>)</span>,<span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">y</font></span>)</span></span><a href="euclid_2.html#K1">)|</a></span> <a href="xxreal_0.html#R1">&lt;=</a> <span class="p1"><a href="euclid.html#K12">|.</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">x</font></span>)</span></span><a href="euclid.html#K12">.|</a></span> <a href="real_1.html#K4">*</a> <span class="p1"><a href="euclid.html#K12">|.</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">y</font></span>)</span></span><a href="euclid.html#K12">.|</a></span>
 
<b>by </b><i><a class="ref" href="euclid_2.html#T37">EUCLID_2:37</a></i>;<br/>
<a NAME="E3:47"/><b>then </b>
 <a href="complex1.html#K18">abs</a> <span class="p1"><a href="euclid_4.html#K5" target="_self">|(</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="euclid_4.html#K5" target="_self">)|</a></span> <a href="xxreal_0.html#R1">&lt;=</a> <span class="p1"><a href="euclid.html#K12">|.</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">x</font></span>)</span></span><a href="euclid.html#K12">.|</a></span> <a href="real_1.html#K4">*</a> <span class="p1"><a href="euclid.html#K12">|.</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">y</font></span>)</span></span><a href="euclid.html#K12">.|</a></span>
 
;<br/>
<a NAME="E4:47"/><b>then </b>
 <a href="complex1.html#K18">abs</a> <span class="p1"><a href="euclid_4.html#K5" target="_self">|(</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="euclid_4.html#K5" target="_self">)|</a></span> <a href="xxreal_0.html#R1">&lt;=</a> <span class="p1"><a href="euclid_4.html#K4" target="_self">|.</a><span class="default"><font color="Maroon">x</font></span><a href="euclid_4.html#K4" target="_self">.|</a></span> <a href="real_1.html#K4">*</a> <span class="p1"><a href="euclid.html#K12">|.</a><span class="default"><span class="p2">(<span class="default"><a href="euclid_4.html#K3" target="_self">Rn2Fin</a> <font color="Maroon">y</font></span>)</span></span><a href="euclid.html#K12">.|</a></span>
 
;<br/>
<b>hence </b><a NAME="E5:47"/>
 <a href="complex1.html#K18">abs</a> <span class="p1"><a href="euclid_4.html#K5" target="_self">|(</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="euclid_4.html#K5" target="_self">)|</a></span> <a href="xxreal_0.html#R1">&lt;=</a> <span class="p1"><a href="euclid_4.html#K4" target="_self">|.</a><span class="default"><font color="Maroon">x</font></span><a href="euclid_4.html#K4" target="_self">.|</a></span> <a href="real_1.html#K4">*</a> <span class="p1"><a href="euclid_4.html#K4" target="_self">|.</a><span class="default"><font color="Maroon">y</font></span><a href="euclid_4.html#K4" target="_self">.|</a></span>
 ;<br/>


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