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<div><i><font color="Green">E20</font></i>: <a class="txt" onclick="hs2(this)" href="javascript:()" title="33_1_1_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>let </b><font color="Maroon">y</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>assume </b><a NAME="E1:33_1_1_1"/>
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">B</font> <a href="relat_1.html#K8">|</a> <font color="Maroon">R</font>
 ;<br/><a NAME="E2:33_1_1_1"/><b>then </b>
( <font color="Maroon">y</font> <a href="hidden.html#R2">in</a> <font color="Maroon">B</font> &amp; <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font> )
 <b>by </b><i><a class="ref" href="relat_1.html#D12">RELAT_1:def 12</a></i>;<br/><b>hence </b><a NAME="E3:33_1_1_1"/>
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <span class="p1"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="zfmisc_1.html#K2">:]</a></span>
 ;<br/></div><b>end;</b></div>
<b>reconsider </b><font color="Maroon">P</font> = <span class="p1"><a href="zfmisc_1.html#K2">[:</a><span class="default"><font color="Maroon">X</font>,<font color="Maroon">Y</font></span><a href="zfmisc_1.html#K2">:]</a></span> as   <a href="relat_1.html#NM1">Relation</a> <b>by </b><i><a class="ref" href="relat_1.html#T6">RELAT_1:6</a></i>;<br/>
<a NAME="E3:33_1_1"/>
<font color="Maroon">B</font> <a href="relat_1.html#K8">|</a> <font color="Maroon">R</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">P</font>
 
<b>by </b><i>, <a class="ref" href="relat_1.html#D3">RELAT_1:def 3</a></i>;<br/>
<b>hence </b><a NAME="E4:33_1_1"/>
<font color="Maroon">B</font> <a href="relat_1.html#K8">|</a> <font color="Maroon">R</font> is    <a href="relset_1.html#M2" target="_self">Relation</a> of <font color="Maroon">X</font>,<font color="Maroon">Y</font>
 <b>by </b><i/>;<br/>


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