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

<b>let </b><font color="Maroon">c<sub>2</sub></font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>

<b>assume </b><a NAME="E1:71_3_1"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="isomichi.html#V5" target="_self">3rd_class</a>
 ;<br/>

<a NAME="E2:71_3_1"/><b>then </b>
 <a href="pre_topc.html#K4">Cl</a> <span class="p1">(<span class="default"><a href="tops_1.html#K1">Int</a> <font color="Maroon">c<sub>2</sub></font></span>)</span>, <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="pre_topc.html#K4">Cl</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="isomichi.html#NR1" target="_self">are_c=-incomparable</a> 
 
<b>by </b><i><a class="ref" href="isomichi.html#D8" target="_self">Def8</a></i>;<br/>
<a NAME="E3:71_3_1"/><b>then </b><i><font color="Green">E38</font></i>: 
( not  <a href="pre_topc.html#K4">Cl</a> <span class="p1">(<span class="default"><a href="tops_1.html#K1">Int</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="tarski.html#R1">c=</a>  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="pre_topc.html#K4">Cl</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> &amp; not  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="pre_topc.html#K4">Cl</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="tarski.html#R1">c=</a>  <a href="pre_topc.html#K4">Cl</a> <span class="p1">(<span class="default"><a href="tops_1.html#K1">Int</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> )
 
<b>by </b><i><a class="ref" href="xboole_0.html#D9">XBOOLE_0:def 9</a></i>;<br/>
<a NAME="E4:71_3_1"/><b>then </b>
not  <a href="pre_topc.html#K4">Cl</a> <span class="p1">(<span class="default"><a href="tops_1.html#K1">Int</a> <font color="Maroon">c<sub>2</sub></font></span>)</span> <a href="xboole_0.html#R2">c&lt;</a>  <a href="tops_1.html#K1">Int</a> <span class="p1">(<span class="default"><a href="pre_topc.html#K4">Cl</a> <font color="Maroon">c<sub>2</sub></font></span>)</span>
 
<b>by </b><i><a class="ref" href="xboole_0.html#D8">XBOOLE_0:def 8</a></i>;<br/>
<b>hence </b><a NAME="E5:71_3_1"/>
( not <font color="Maroon">c<sub>2</sub></font> is <a href="isomichi.html#V3" target="_self">1st_class</a> &amp; not <font color="Maroon">c<sub>2</sub></font> is <a href="isomichi.html#V4" target="_self">2nd_class</a> )
 <b>by </b><i><a class="txt" href="isomichi.html#E3:71_3_1"><i><font color="Green">E38</font></i></a>, <a class="ref" href="isomichi.html#D6" target="_self">Def6</a>, <a class="ref" href="isomichi.html#D7" target="_self">Def7</a></i>;<br/>


</div>
