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

<b>let </b><font color="Maroon">E1</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">E2</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:10_1_2"/><i><font color="Green">E59</font></i>: 
( <font color="Maroon">E1</font> is <a href="intpro_1.html#V7" target="_self">MC-closed</a> &amp; ( for <font color="Olive">E</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">E</font> is <a href="intpro_1.html#V7" target="_self">MC-closed</a> holds <br/><font color="Maroon">E1</font> <a href="tarski.html#R1">c=</a> <font color="Olive">E</font> ) )
 <b>and </b><br/><a NAME="E2:10_1_2"/><i><font color="Green">E60</font></i>: 
( <font color="Maroon">E2</font> is <a href="intpro_1.html#V7" target="_self">MC-closed</a> &amp; ( for <font color="Olive">E</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">E</font> is <a href="intpro_1.html#V7" target="_self">MC-closed</a> holds <br/><font color="Maroon">E2</font> <a href="tarski.html#R1">c=</a> <font color="Olive">E</font> ) )
 ;<br/>

<a NAME="E3:10_1_2"/>
( <font color="Maroon">E1</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">E2</font> &amp; <font color="Maroon">E2</font> <a href="tarski.html#R1">c=</a> <font color="Maroon">E1</font> )
 
<b>by </b><i>, </i>;<br/>
<b>hence </b><a NAME="E4:10_1_2"/>
<font color="Maroon">E1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">E2</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D10">XBOOLE_0:def 10</a></i>;<br/>


</div>
