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<b>let </b><font color="Maroon">S</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#NM1">Element</a> of <font color="Maroon">S</font>, <font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">S</font>;<br/><b>let </b><font color="Maroon">i</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span>;<br/>





<b>set </b><font color="Maroon">N</font> =  <a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font>;<br/>
<b>reconsider </b><font color="Maroon">I</font> = <font color="Maroon">i</font> as    <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a>  <b>by </b><i/>;<br/>
<a NAME="E2:20"/><i><font color="Green">E43</font></i>: 
<span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="waybel_0.html#K2">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="waybel17.html#K1" target="_self">,...</a> </span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font>
 
<b>by </b><i/>;<br/>
<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a> ] <b>means </b> ex <font color="Olive">k</font> being   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a>  st <font color="Maroon">a<sub>1</sub></font> <a href="hidden.html#R1">=</a> 2 <a href="nat_1.html#K2">*</a> <font color="Olive">k</font>;<br/>
<div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="20_1"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:20_1"/>
( <font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">I</font>] or  not <font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">I</font>] )
 </span>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="20_1_1"><b>suppose </b></a><a NAME="E1:20_1_1"/>
<font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">I</font>]
 ;<br/><div class="add"><b>hence </b><a NAME="E2:20_1_1"/>
( <span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="waybel_0.html#K2">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font> or <span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="waybel_0.html#K2">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">b</font> )
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="20_1_2"><b>suppose </b></a><a NAME="E1:20_1_2"/>
 not <font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">I</font>]
 ;<br/><div class="add"><b>hence </b><a NAME="E2:20_1_2"/>
( <span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="waybel_0.html#K2">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font> or <span class="p1">(<span class="default"><a href="waybel17.html#K3" target="_self">Net-Str</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="waybel_0.html#K2">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">b</font> )
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div></div><b>end;</b></div>

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