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<b>let </b><font color="Maroon">c<sub>1</sub></font>, <font color="Maroon">c<sub>2</sub></font> be   <a href="relat_1.html#NM1">Relation</a>;<br/><b>let </b><font color="Maroon">c<sub>3</sub></font>, <font color="Maroon">c<sub>4</sub></font> be    <a href="hidden.html#M1">set</a> ;<br/>



<b>assume </b><b>that </b><br/><a NAME="E1:179"/><i><font color="Green">E76</font></i>: 
<font color="Maroon">c<sub>3</sub></font> <a href="tarski.html#R1">c=</a> <font color="Maroon">c<sub>4</sub></font>
 <b>and </b><br/><a NAME="E2:179"/><i><font color="Green">E77</font></i>: 
<font color="Maroon">c<sub>1</sub></font> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>4</sub></font>
 ;<br/>

<a NAME="E3:179"/><i><font color="Green">E78</font></i>: 
<font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>4</sub></font> <a href="xboole_0.html#K3">/\</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="txt" href="relat_1.html#E1:179"><i><font color="Green">E76</font></i></a>, <a class="ref" href="xboole_1.html#T28">XBOOLE_1:28</a></i>;<br/>
<b>hence </b><font color="Maroon">c<sub>1</sub></font> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>3</sub></font> = 
<span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>4</sub></font></span>)</span> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>3</sub></font>
<b>by </b><i><a class="ref" href="relat_1.html#T100" target="_self">Th100</a></i>
<br/>.= 
<font color="Maroon">c<sub>2</sub></font> <a href="relat_1.html#K7" target="_self">|</a> <font color="Maroon">c<sub>3</sub></font>
<b>by </b><i><a class="txt" href="relat_1.html#E2:179"><i><font color="Green">E77</font></i></a>, <a class="txt" href="relat_1.html#E3:179"><i><font color="Green">E78</font></i></a>, <a class="ref" href="relat_1.html#T100" target="_self">Th100</a></i>
;<br/><br/>


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