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<span class="kw">let </span><font color="Maroon" title="c1">U1</font>, <font color="Maroon" title="c2">U2</font> be   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide"> ( <font color="Maroon" title="c1">U1</font> <a href="xboole_0.html#K2" title="XBOOLE_0:func.2">\/</a> <font color="Maroon" title="c2">U2</font> is   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a> &amp; <font color="Maroon" title="c1">U1</font> <a href="xboole_0.html#K3" title="XBOOLE_0:func.3">/\</a> <font color="Maroon" title="c2">U2</font> is   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a> )</span><br/>



<a NAME="E1:58"/>
<font color="Maroon" title="c1">U1</font>,<font color="Maroon" title="c2">U2</font> <a href="xboole_0.html#R3" title="XBOOLE_0:pred.3">are_c=-comparable</a> 
 
<span class="kw">by</span> <span class="lab"><a class="ref" href="classes2.html#T58" target="_self" title="CLASSES2:th.58">Th58</a></span>;<br/>
<a NAME="E2:58"/><span class="kw">then </span>
( <font color="Maroon" title="c1">U1</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c2">U2</font> or <font color="Maroon" title="c2">U2</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Maroon" title="c1">U1</font> )
 
<span class="kw">by</span> <span class="lab"><a class="ref" href="xboole_0.html#D9" title="XBOOLE_0:def.9">XBOOLE_0:def 9</a></span>;<br/>
<span class="kw">hence </span><a NAME="E3:58"/>
( <font color="Maroon" title="c1">U1</font> <a href="xboole_0.html#K2" title="XBOOLE_0:func.2">\/</a> <font color="Maroon" title="c2">U2</font> is   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a> &amp; <font color="Maroon" title="c1">U1</font> <a href="xboole_0.html#K3" title="XBOOLE_0:func.3">/\</a> <font color="Maroon" title="c2">U2</font> is   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a> )
 <span class="kw">by</span> <span class="lab"><a class="ref" href="xboole_1.html#T12" title="XBOOLE_1:th.12">XBOOLE_1:12</a>, <a class="ref" href="xboole_1.html#T28" title="XBOOLE_1:th.28">XBOOLE_1:28</a></span>; <a class="txt" onclick="hs(this)" href="javascript:()"><span class="comment"><font color="Red">::  thesis: </font></span></a><span class="hide"> verum</span><br/>


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