<?xml version="1.0"?>
<div class="add">

<div><b>hereby </b>
<div class="add"><b>assume </b><a NAME="E1:96_1_1_1"/>
<font color="Maroon">X</font> <a href="roughs_1.html#R4" target="_self">_=</a> <font color="Maroon">Y</font>
 ;<br/><a NAME="E2:96_1_1_1"/><b>then </b>
 <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">X</font> <a href="hidden.html#R1">=</a>  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">Y</font>
 <b>by </b><i/>;<br/><b>hence </b><a NAME="E3:96_1_1_1"/>
( <font color="Maroon">X</font> <a href="roughs_1.html#R1" target="_self">_c=</a> <font color="Maroon">Y</font> &amp; <font color="Maroon">Y</font> <a href="roughs_1.html#R1" target="_self">_c=</a> <font color="Maroon">X</font> )
 <b>by </b><i/>;<br/></div>
<b>end;</b></div>

<b>assume </b><a NAME="E2:96_1_1"/>
( <font color="Maroon">X</font> <a href="roughs_1.html#R1" target="_self">_c=</a> <font color="Maroon">Y</font> &amp; <font color="Maroon">Y</font> <a href="roughs_1.html#R1" target="_self">_c=</a> <font color="Maroon">X</font> )
 ;<br/>

<a NAME="E3:96_1_1"/><b>then </b>
(  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">X</font> <a href="tarski.html#R1">c=</a>  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">Y</font> &amp;  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">Y</font> <a href="tarski.html#R1">c=</a>  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">X</font> )
 
<b>by </b><i/>;<br/>
<a NAME="E4:96_1_1"/><b>then </b>
 <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">X</font> <a href="hidden.html#R1">=</a>  <a href="roughs_1.html#K3" target="_self">LAp</a> <font color="Maroon">Y</font>
 
<b>by </b><i><a class="ref" href="xboole_0.html#D10">XBOOLE_0:def 10</a></i>;<br/>
<b>hence </b><a NAME="E5:96_1_1"/>
<font color="Maroon">X</font> <a href="roughs_1.html#R4" target="_self">_=</a> <font color="Maroon">Y</font>
 <b>by </b><i/>;<br/>


</div>
