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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">k</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> ;<br/>



<b>set </b><font color="Maroon">F</font> = <span class="p1">{<span class="default"> <font color="Olive">f</font> where <font color="Olive">f</font> is   <a href="funct_2.html#NM1">Function</a> of <font color="Maroon">n</font>,<font color="Maroon">k</font> : ( <font color="Olive">f</font> is <a href="funct_2.html#V2">onto</a> &amp; <font color="Olive">f</font> is <a href="stirl2_1.html#V1" target="_self">"increasing</a> ) </span>}</span> ;<br/>
<a NAME="E1:31"/>
<span class="p1">{<span class="default"> <font color="Olive">f</font> where <font color="Olive">f</font> is   <a href="funct_2.html#NM1">Function</a> of <font color="Maroon">n</font>,<font color="Maroon">k</font> : ( <font color="Olive">f</font> is <a href="funct_2.html#V2">onto</a> &amp; <font color="Olive">f</font> is <a href="stirl2_1.html#V1" target="_self">"increasing</a> ) </span>}</span>  is <a href="finset_1.html#V1">finite</a>
 
<b>by </b><i/>;<br/>
<b>then consider </b><font color="Maroon">m</font> being    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> <b> such that </b><br/><a NAME="E3:31"/><i><font color="Green">E38</font></i>: 
<span class="p1">{<span class="default"> <font color="Olive">f</font> where <font color="Olive">f</font> is   <a href="funct_2.html#NM1">Function</a> of <font color="Maroon">n</font>,<font color="Maroon">k</font> : ( <font color="Olive">f</font> is <a href="funct_2.html#V2">onto</a> &amp; <font color="Olive">f</font> is <a href="stirl2_1.html#V1" target="_self">"increasing</a> ) </span>}</span> ,<font color="Maroon">m</font> <a href="wellord2.html#R2">are_equipotent</a> 
 <b>by </b><i><a class="ref" href="card_1.html#T74">CARD_1:74</a></i>;<br/>
<a NAME="E4:31"/>
(  <a href="card_1.html#K1">Card</a> <span class="p1">{<span class="default"> <font color="Olive">f</font> where <font color="Olive">f</font> is   <a href="funct_2.html#NM1">Function</a> of <font color="Maroon">n</font>,<font color="Maroon">k</font> : ( <font color="Olive">f</font> is <a href="funct_2.html#V2">onto</a> &amp; <font color="Olive">f</font> is <a href="stirl2_1.html#V1" target="_self">"increasing</a> ) </span>}</span>  <a href="hidden.html#R1">=</a>  <a href="card_1.html#K1">Card</a> <font color="Maroon">m</font> &amp;  <a href="card_1.html#K1">Card</a> <font color="Maroon">m</font> <a href="hidden.html#R1">=</a> <font color="Maroon">m</font> )
 
<b>by </b><i>, <a class="ref" href="card_1.html#T21">CARD_1:21</a>, <a class="ref" href="card_1.html#T66">CARD_1:66</a></i>;<br/>
<b>hence </b><a NAME="E5:31"/>
 <a href="card_1.html#K1">Card</a> <span class="p1">{<span class="default"> <font color="Olive">f</font> where <font color="Olive">f</font> is   <a href="funct_2.html#NM1">Function</a> of <font color="Maroon">n</font>,<font color="Maroon">k</font> : ( <font color="Olive">f</font> is <a href="funct_2.html#V2">onto</a> &amp; <font color="Olive">f</font> is <a href="stirl2_1.html#V1" target="_self">"increasing</a> ) </span>}</span>  is    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K5">NAT</a> 
 ;<br/>


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