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<b>let </b><font color="Maroon">I</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">C</font> be   <a href="cat_1.html#NM4">Category</a>;<br/><b>let </b><font color="Maroon">f</font> be   <a href="cat_1.html#NM2">Morphism</a> of <font color="Maroon">C</font>;<br/>





<b>set </b><font color="Maroon">F</font> = <font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <font color="Maroon">f</font>;<br/>
<b>set </b><font color="Maroon">F'</font> = <font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <span class="p1">(<span class="default"><a href="cat_1.html#K3">cod</a> <font color="Maroon">f</font></span>)</span>;<br/>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="11_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:11_1"/><i><font color="Green">E38</font></i>: 
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">I</font>
 ;<br/><a NAME="E2:11_1"/><b>then </b>
( <span class="p1">(<span class="default"><font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <font color="Maroon">f</font></span>)</span> <a href="finseq_4.html#K4">/.</a> <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Maroon">f</font> &amp; <span class="p1">(<span class="default"><font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <span class="p2">(<span class="default"><a href="cat_1.html#K3">cod</a> <font color="Maroon">f</font></span>)</span></span>)</span> <a href="finseq_4.html#K4">/.</a> <font color="Maroon">x</font> <a href="hidden.html#R1">=</a>  <a href="cat_1.html#K3">cod</a> <font color="Maroon">f</font> )
 <b>by </b><i/>;<br/><b>hence </b><a NAME="E3:11_1"/>
<span class="p1">(<span class="default"><a href="cat_3.html#K4" target="_self">cods</a> <span class="p2">(<span class="default"><font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <font color="Maroon">f</font></span>)</span></span>)</span> <a href="finseq_4.html#K4">/.</a> <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <span class="p2">(<span class="default"><a href="cat_1.html#K3">cod</a> <font color="Maroon">f</font></span>)</span></span>)</span> <a href="finseq_4.html#K4">/.</a> <font color="Maroon">x</font>
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div>
<b>hence </b><a NAME="E2:11"/>
 <a href="cat_3.html#K4" target="_self">cods</a> <span class="p1">(<span class="default"><font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <font color="Maroon">f</font></span>)</span> <a href="funct_2.html#R2">=</a> <font color="Maroon">I</font> <a href="cat_3.html#K1" target="_self">--&gt;</a> <span class="p1">(<span class="default"><a href="cat_1.html#K3">cod</a> <font color="Maroon">f</font></span>)</span>
 <b>by </b><i/>;<br/>


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