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<b>let </b><font color="Maroon">G</font> be  non <a href="struct_0.html#V3">empty</a>  <a href="lang1.html#L1" target="_self">DTConstrStr</a> ;<br/><b>let </b><font color="Maroon">n</font> be   <a href="lang1.html#NM2">String</a> of <font color="Maroon">G</font>;<br/><b>let </b><font color="Maroon">m</font> be   <a href="lang1.html#NM2">String</a> of <font color="Maroon">G</font>;<br/>





<b>assume </b><a NAME="E1:20"/><i><font color="Green">E35</font></i>: 
<font color="Maroon">n</font> <a href="lang1.html#R2" target="_self">==&gt;</a> <font color="Maroon">m</font>
 ;<br/>

<b>take </b><font color="Maroon">p</font> = <span class="p1"><a href="lang1.html#K4" target="_self">&lt;*</a><span class="default"><font color="Maroon">n</font>,<font color="Maroon">m</font></span><a href="lang1.html#K4" target="_self">*&gt;</a></span>; <i><font color="Red">:: according to </font></i><a class="ref" href="lang1.html#D5" target="_self">LANG1:def 5</a><br/>

<a NAME="E2:20"/><i><font color="Green">E48</font></i>: 
(  <a href="finseq_1.html#K3">len</a> <font color="Maroon">p</font> <a href="hidden.html#R1">=</a> 2 &amp; <font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> 1 <a href="hidden.html#R1">=</a> <font color="Maroon">n</font> &amp; <font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> 2 <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> )
 
<b>by </b><i><a class="ref" href="finseq_1.html#T61">FINSEQ_1:61</a></i>;<br/>
<b>hence </b><a NAME="E3:20"/>
(  <a href="finseq_1.html#K3">len</a> <font color="Maroon">p</font> <a href="xxreal_0.html#NR2" target="_self">&gt;=</a> 1 &amp; <font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> 1 <a href="hidden.html#R1">=</a> <font color="Maroon">n</font> &amp; <font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">p</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> )
 ;<br/>

<b>let </b><font color="Maroon">i</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> ;<br/>

<b>assume </b><a NAME="E4:20"/><i><font color="Green">E49</font></i>: 
( <font color="Maroon">i</font> <a href="xxreal_0.html#NR2" target="_self">&gt;=</a> 1 &amp; <font color="Maroon">i</font> <a href="xxreal_0.html#NR3" target="_self">&lt;</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">p</font> )
 ;<br/>

<a NAME="E5:20"/>
2 <a href="hidden.html#R1">=</a> 1 <a href="nat_1.html#K1">+</a> 1
 
;<br/>
<a NAME="E6:20"/><b>then </b>
<font color="Maroon">i</font> <a href="xxreal_0.html#R1">&lt;=</a> 1
 
<b>by </b><i>, , <a class="ref" href="nat_1.html#T38">NAT_1:38</a></i>;<br/>
<a NAME="E7:20"/><b>then </b><i><font color="Green">E50</font></i>: 
<font color="Maroon">i</font> <a href="hidden.html#R1">=</a> 1
 
<b>by </b><i>, <a class="ref" href="xxreal_0.html#T1">XXREAL_0:1</a></i>;<br/>
<b>take </b><font color="Maroon">a</font> = <font color="Maroon">n</font>;<br/>

<b>take </b><font color="Maroon">b</font> = <font color="Maroon">m</font>;<br/>

<b>thus </b><a NAME="E8:20"/>
<font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> <font color="Maroon">i</font> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i>, <a class="ref" href="finseq_1.html#T61">FINSEQ_1:61</a></i>;<br/>

<b>thus </b><a NAME="E9:20"/>
<font color="Maroon">p</font> <a href="funct_1.html#K1">.</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="nat_1.html#K1">+</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">b</font>
 <b>by </b><i>, <a class="ref" href="finseq_1.html#T61">FINSEQ_1:61</a></i>;<br/>

<b>thus </b><a NAME="E10:20"/>
<font color="Maroon">a</font> <a href="lang1.html#R2" target="_self">==&gt;</a> <font color="Maroon">b</font>
 <b>by </b><i/>;<br/>


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