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<b>let </b><font color="Maroon">f</font> be   <a href="funct_1.html#NM1">Function</a>, <font color="Maroon">g</font> be   <a href="funct_1.html#NM1">Function</a>;<br/>

<a NAME="E1:45"/><i><font color="Green">E29</font></i>: 
(  <a href="card_1.html#K1">Card</a> <font color="Maroon">f</font> <a href="hidden.html#R1">=</a>  <a href="card_1.html#K1">Card</a> <span class="p1">(<span class="default"><a href="relat_1.html#K1">dom</a> <font color="Maroon">f</font></span>)</span> &amp;  <a href="card_1.html#K1">Card</a> <font color="Maroon">g</font> <a href="hidden.html#R1">=</a>  <a href="card_1.html#K1">Card</a> <span class="p1">(<span class="default"><a href="relat_1.html#K1">dom</a> <font color="Maroon">g</font></span>)</span> )
 
<b>by </b><i/>;<br/>
<div><b>hereby </b>
<div class="add"><b>assume </b><a NAME="E1:45_1"/>
 <a href="relat_1.html#K1">dom</a> <font color="Maroon">f</font>, <a href="relat_1.html#K1">dom</a> <font color="Maroon">g</font> <a href="tarski.html#R2">are_equipotent</a> 
 ;<br/><a NAME="E2:45_1"/><b>then </b>
 <a href="card_1.html#K1">Card</a> <span class="p1">(<span class="default"><a href="relat_1.html#K1">dom</a> <font color="Maroon">f</font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="card_1.html#K1">Card</a> <span class="p1">(<span class="default"><a href="relat_1.html#K1">dom</a> <font color="Maroon">g</font></span>)</span>
 <b>by </b><i><a class="ref" href="card_1.html#T21">CARD_1:21</a></i>;<br/><b>hence </b><a NAME="E3:45_1"/>
<font color="Maroon">f</font>,<font color="Maroon">g</font> <a href="tarski.html#R2">are_equipotent</a> 
 <b>by </b><i>, <a class="ref" href="card_1.html#T21">CARD_1:21</a></i>;<br/></div>
<b>end;</b></div>

<b>assume </b><a NAME="E3:45"/>
<font color="Maroon">f</font>,<font color="Maroon">g</font> <a href="tarski.html#R2">are_equipotent</a> 
 ;<br/>

<a NAME="E4:45"/><b>then </b>
 <a href="card_1.html#K1">Card</a> <font color="Maroon">f</font> <a href="hidden.html#R1">=</a>  <a href="card_1.html#K1">Card</a> <font color="Maroon">g</font>
 
<b>by </b><i><a class="ref" href="card_1.html#T21">CARD_1:21</a></i>;<br/>
<b>hence </b><a NAME="E5:45"/>
 <a href="relat_1.html#K1">dom</a> <font color="Maroon">f</font>, <a href="relat_1.html#K1">dom</a> <font color="Maroon">g</font> <a href="tarski.html#R2">are_equipotent</a> 
 <b>by </b><i>, <a class="ref" href="card_1.html#T21">CARD_1:21</a></i>;<br/>


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