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<b>let </b><font color="Maroon" title="c1">I</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c2">C</font> be   <a href="cat_1.html#NM4" title="CAT_1:NM.4">Category</a>;<br/><b>let </b><font color="Maroon" title="c3">F</font> be   <a href="funct_2.html#NM1" title="FUNCT_2:NM.1">Function</a> of <font color="Maroon" title="c1">I</font>,the <a href="cat_1.html#U2" title="CAT_1:sel.2">Morphisms</a> of <font color="Maroon" title="c2">C</font>;<br/>





<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="21_1"><b>now </b></a><div class="add"><b>let </b><font color="Maroon" title="c4">x</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>assume </b><a NAME="E1:21_1"/><i><font color="Green" title="E13">A1</font></i>: 
<font color="Maroon" title="c4">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">I</font>
 ;<br/><b>hence </b><span class="p1">(<span class="default"><a href="cat_3.html#K6" title="CAT_3:func.6">opp</a> <span class="p2">(<span class="default"><font color="Maroon" title="c3">F</font> <a href="cat_3.html#K5" title="CAT_3:func.5">opp</a> </span>)</span></span>)</span> <a href="finseq_4.html#K4" title="FINSEQ_4:func.4">/.</a> <font color="Maroon" title="c4">x</font> = 
 <a href="oppcat_1.html#K6" title="OPPCAT_1:func.6">opp</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c3">F</font> <a href="cat_3.html#K5" title="CAT_3:func.5">opp</a> </span>)</span> <a href="finseq_4.html#K4" title="FINSEQ_4:func.4">/.</a> <font color="Maroon" title="c4">x</font></span>)</span>
<b>by </b><i><a class="ref" href="cat_3.html#D6" target="_self" title="CAT_3:def.6">Def6</a></i>
<br/>.= 
 <a href="oppcat_1.html#K6" title="OPPCAT_1:func.6">opp</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><font color="Maroon" title="c3">F</font> <a href="finseq_4.html#K4" title="FINSEQ_4:func.4">/.</a> <font color="Maroon" title="c4">x</font></span>)</span> <a href="oppcat_1.html#K5" title="OPPCAT_1:func.5">opp</a> </span>)</span>
<b>by </b><i><a class="txt" href="cat_3.html#E1:21_1"><i><font color="Green" title="E13">A1</font></i></a>, <a class="ref" href="cat_3.html#D5" target="_self" title="CAT_3:def.5">Def5</a></i>
<br/>.= 
<font color="Maroon" title="c3">F</font> <a href="finseq_4.html#K4" title="FINSEQ_4:func.4">/.</a> <font color="Maroon" title="c4">x</font>
<b>by </b><i><a class="ref" href="oppcat_1.html#T7" title="OPPCAT_1:th.7">OPPCAT_1:7</a></i>
;<br/><br/></div><b>end;</b></div>
<b>hence </b><a NAME="E2:21"/>
 <a href="cat_3.html#K6" title="CAT_3:func.6">opp</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">F</font> <a href="cat_3.html#K5" title="CAT_3:func.5">opp</a> </span>)</span> <a href="funct_2.html#R2" title="FUNCT_2:pred.2">=</a> <font color="Maroon" title="c3">F</font>
 <b>by </b><i><a class="ref" href="cat_3.html#T1" target="_self" title="CAT_3:th.1">Th1</a></i>;<br/>


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