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<b>let </b><font color="Maroon">C</font> be   <a href="cat_4.html#NM2">Cocartesian_category</a>;<br/><b>let </b><font color="Maroon">a</font> be   <a href="cat_1.html#NM1">Object</a> of <font color="Maroon">C</font>;<br/><b>let </b><font color="Maroon">c</font> be   <a href="cat_1.html#NM1">Object</a> of <font color="Maroon">C</font>;<br/><b>let </b><font color="Maroon">b</font> be   <a href="cat_1.html#NM1">Object</a> of <font color="Maroon">C</font>;<br/><b>let </b><font color="Maroon">f</font> be    <a href="cat_1.html#M1">Morphism</a> of <font color="Maroon">a</font>,<font color="Maroon">c</font>, <font color="Maroon">k</font> be    <a href="cat_1.html#M1">Morphism</a> of <font color="Maroon">a</font>,<font color="Maroon">c</font>;<br/><b>let </b><font color="Maroon">g</font> be    <a href="cat_1.html#M1">Morphism</a> of <font color="Maroon">b</font>,<font color="Maroon">c</font>, <font color="Maroon">h</font> be    <a href="cat_1.html#M1">Morphism</a> of <font color="Maroon">b</font>,<font color="Maroon">c</font>;<br/>











<b>assume </b><a NAME="E1:95"/>
(  <a href="cat_1.html#K6">Hom</a> <font color="Maroon">a</font>,<font color="Maroon">c</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a>  &amp;  <a href="cat_1.html#K6">Hom</a> <font color="Maroon">b</font>,<font color="Maroon">c</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="xboole_0.html#K1">{}</a>  )
 ;<br/>

<a NAME="E2:95"/><b>then </b>
( <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">f</font>,<font color="Maroon">g</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> <a href="cat_1.html#K9">*</a> <span class="p1">(<span class="default"><a href="cat_4.html#K25" target="_self">in1</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">f</font> &amp; <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">k</font>,<font color="Maroon">h</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> <a href="cat_1.html#K9">*</a> <span class="p1">(<span class="default"><a href="cat_4.html#K25" target="_self">in1</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">k</font> &amp; <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">f</font>,<font color="Maroon">g</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> <a href="cat_1.html#K9">*</a> <span class="p1">(<span class="default"><a href="cat_4.html#K26" target="_self">in2</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">g</font> &amp; <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">k</font>,<font color="Maroon">h</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> <a href="cat_1.html#K9">*</a> <span class="p1">(<span class="default"><a href="cat_4.html#K26" target="_self">in2</a> <font color="Maroon">a</font>,<font color="Maroon">b</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">h</font> )
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E3:95"/>
(  not <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">f</font>,<font color="Maroon">g</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> <a href="hidden.html#R1">=</a> <span class="p1"><a href="cat_4.html#K27" target="_self">[$</a><span class="default"><font color="Maroon">k</font>,<font color="Maroon">h</font></span><a href="cat_4.html#K27" target="_self">$]</a></span> or ( <font color="Maroon">f</font> <a href="hidden.html#R1">=</a> <font color="Maroon">k</font> &amp; <font color="Maroon">g</font> <a href="hidden.html#R1">=</a> <font color="Maroon">h</font> ) )
 ;<br/>


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