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<b>let </b><font color="Maroon">D1</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> , <font color="Maroon">D2</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">n</font> be   <a href="nat_1.html#NM1">Nat</a>, <font color="Maroon">m</font> be   <a href="nat_1.html#NM1">Nat</a>;<br/>



<b>assume </b><a NAME="E1:1"/><i><font color="Green">E23</font></i>: 
<font color="Maroon">n</font> <a href="finseq_2.html#K4">-tuples_on</a> <font color="Maroon">D1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> <a href="finseq_2.html#K4">-tuples_on</a> <font color="Maroon">D2</font>
 ;<br/>

<b>consider </b><font color="Maroon">p</font> being    <a href="finseq_2.html#M2">Element</a> of <font color="Maroon">n</font> <a href="finseq_2.html#K4">-tuples_on</a> <font color="Maroon">D1</font>;<br/>
<a NAME="E3:1"/>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">m</font> <a href="finseq_2.html#K4">-tuples_on</a> <font color="Maroon">D2</font>
 
<b>by </b><i/>;<br/>
<a NAME="E4:1"/><b>then </b>
<font color="Maroon">p</font> <a href="hidden.html#R2">in</a> <span class="p1">{<span class="default"> <font color="Olive">w</font> where <font color="Olive">w</font> is    <a href="finseq_2.html#M2">Element</a> of <font color="Maroon">D2</font> <a href="finseq_2.html#K3">*</a>  :  <a href="finseq_1.html#K3">len</a> <font color="Olive">w</font> <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> </span>}</span> 
 
;<br/>
<b>then consider </b><font color="Maroon">w</font> being    <a href="finseq_2.html#M2">Element</a> of <font color="Maroon">D2</font> <a href="finseq_2.html#K3">*</a> <b> such that </b><br/><a NAME="E6:1"/><i><font color="Green">E26</font></i>: 
( <font color="Maroon">p</font> <a href="hidden.html#R1">=</a> <font color="Maroon">w</font> &amp;  <a href="finseq_1.html#K3">len</a> <font color="Maroon">w</font> <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> )
 ;<br/>
<b>thus </b><a NAME="E7:1"/>
<font color="Maroon">m</font> <a href="hidden.html#R1">=</a> <font color="Maroon">n</font>
 <b>by </b><i>, <a class="ref" href="finseq_2.html#T109">FINSEQ_2:109</a></i>;<br/>


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