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<b>let </b><font color="Maroon">T</font> be  non <a href="struct_0.html#V3">empty</a>  <a href="orders_2.html#L1">RelStr</a> ;<br/><b>let </b><font color="Maroon">A</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font>;<br/>



<a NAME="E1:18"/>
( ( for <font color="Olive">n</font> being   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a> <br/> for <font color="Olive">B</font> being  <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">T</font>  st <font color="Olive">B</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><a href="fintopo3.html#K2" target="_self">Fcl</a> <font color="Maroon">A</font></span>)</span> <a href="funct_2.html#K3">.</a> <font color="Olive">n</font> holds <br/><span class="p1">(<span class="default"><a href="fintopo3.html#K2" target="_self">Fcl</a> <font color="Maroon">A</font></span>)</span> <a href="funct_2.html#K3">.</a> <span class="p1">(<span class="default"><font color="Olive">n</font> <a href="nat_1.html#K1">+</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Olive">B</font> <a href="fin_topo.html#K9">^b</a>  ) &amp; <span class="p1">(<span class="default"><a href="fintopo3.html#K2" target="_self">Fcl</a> <font color="Maroon">A</font></span>)</span> <a href="funct_2.html#K3">.</a> 0 <a href="hidden.html#R1">=</a> <font color="Maroon">A</font> )
 
<b>by </b><i/>;<br/>
<a NAME="E2:18"/><b>then </b>
<span class="p1">(<span class="default"><a href="fintopo3.html#K2" target="_self">Fcl</a> <font color="Maroon">A</font></span>)</span> <a href="funct_2.html#K3">.</a> <span class="p1">(<span class="default">0 <a href="nat_1.html#K1">+</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">A</font> <a href="fin_topo.html#K9">^b</a> 
 
;<br/>
<b>hence </b><a NAME="E3:18"/>
 <a href="fintopo3.html#K3" target="_self">Fcl</a> <font color="Maroon">A</font>,1 <a href="hidden.html#R1">=</a> <font color="Maroon">A</font> <a href="fin_topo.html#K9">^b</a> 
 ;<br/>


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