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<b>let </b><font color="Maroon">X</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">R</font> be   <a href="relat_1.html#NM1">Relation</a>;<br/><b>let </b><font color="Maroon">P2</font> be   <a href="relat_1.html#NM1">Relation</a>;<br/><b>let </b><font color="Maroon">P1</font> be   <a href="relat_1.html#NM1">Relation</a>;<br/>







<b>assume </b><b>that </b><br/><a NAME="E1:79"/>
 <a href="relat_1.html#K1" target="_self">dom</a> <font color="Maroon">R</font> <a href="hidden.html#R1">=</a> <font color="Maroon">X</font>
 <b>and </b><br/><a NAME="E2:79"/><i><font color="Green">E31</font></i>: 
 <a href="relat_1.html#K2" target="_self">rng</a> <font color="Maroon">P2</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">X</font>
 <b>and </b><br/><a NAME="E3:79"/><i><font color="Green">E36</font></i>: 
<font color="Maroon">P2</font> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">R</font> <a href="hidden.html#R1">=</a>  <a href="relat_1.html#K6" target="_self">id</a> <span class="p1">(<span class="default"><a href="relat_1.html#K1" target="_self">dom</a> <font color="Maroon">P1</font></span>)</span>
 <b>and </b><br/><a NAME="E4:79"/><i><font color="Green">E37</font></i>: 
<font color="Maroon">R</font> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">P1</font> <a href="hidden.html#R1">=</a>  <a href="relat_1.html#K6" target="_self">id</a> <font color="Maroon">X</font>
 ;<br/>

<a NAME="E5:79"/>
( <span class="p1">(<span class="default"><font color="Maroon">P2</font> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">R</font></span>)</span> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">P1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">P2</font> <a href="relat_1.html#K5" target="_self">*</a> <span class="p1">(<span class="default"><font color="Maroon">R</font> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">P1</font></span>)</span> &amp; <span class="p1">(<span class="default"><a href="relat_1.html#K6" target="_self">id</a> <span class="p2">(<span class="default"><a href="relat_1.html#K1" target="_self">dom</a> <font color="Maroon">P1</font></span>)</span></span>)</span> <a href="relat_1.html#K5" target="_self">*</a> <font color="Maroon">P1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">P1</font> &amp; <font color="Maroon">P2</font> <a href="relat_1.html#K5" target="_self">*</a> <span class="p1">(<span class="default"><a href="relat_1.html#K6" target="_self">id</a> <font color="Maroon">X</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">P2</font> )
 
<b>by </b><i>, , <a class="txt" href="relat_1.html#E3:79"><i><font color="Green">E36</font></i></a>, <a class="txt" href="relat_1.html#E4:79"><i><font color="Green">E37</font></i></a></i>;<br/>
<b>hence </b><a NAME="E6:79"/>
<font color="Maroon">P1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">P2</font>
 <b>by </b><i>, </i>;<br/>


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