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<b>let </b><font color="Maroon">U1</font> be   <a href="classes2.html#NM1">Universe</a>;<br/><b>let </b><font color="Maroon">U2</font> be   <a href="classes2.html#NM1">Universe</a>;<br/><b>let </b><font color="Maroon">U3</font> be   <a href="classes2.html#NM1">Universe</a>;<br/>





<b>assume </b><a NAME="E1:53"/><i><font color="Green">E27</font></i>: 
( <font color="Maroon">U1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">U2</font> &amp; <font color="Maroon">U2</font> <a href="hidden.html#R2">in</a> <font color="Maroon">U3</font> )
 ;<br/>

<a NAME="E2:53"/><i><font color="Green">E28</font></i>: 
( <font color="Maroon">U1</font> <a href="hidden.html#R1">=</a>  <a href="classes1.html#K4">Rank</a> <span class="p1">(<span class="default"><a href="ordinal1.html#K3">On</a> <font color="Maroon">U1</font></span>)</span> &amp; <font color="Maroon">U2</font> <a href="hidden.html#R1">=</a>  <a href="classes1.html#K4">Rank</a> <span class="p1">(<span class="default"><a href="ordinal1.html#K3">On</a> <font color="Maroon">U2</font></span>)</span> &amp; <font color="Maroon">U3</font> <a href="hidden.html#R1">=</a>  <a href="classes1.html#K4">Rank</a> <span class="p1">(<span class="default"><a href="ordinal1.html#K3">On</a> <font color="Maroon">U3</font></span>)</span> )
 
<b>by </b><i><a class="ref" href="classes2.html#T4" target="_self">Th4</a></i>;<br/>
<a NAME="E3:53"/><b>then </b>
(  <a href="ordinal1.html#K3">On</a> <font color="Maroon">U1</font> <a href="hidden.html#R2">in</a>  <a href="ordinal1.html#K3">On</a> <font color="Maroon">U2</font> &amp;  <a href="ordinal1.html#K3">On</a> <font color="Maroon">U2</font> <a href="hidden.html#R2">in</a>  <a href="ordinal1.html#K3">On</a> <font color="Maroon">U3</font> )
 
<b>by </b><i><a class="ref" href="classes2.html#T10" target="_self">Th10</a>, <a class="ref" href="classes1.html#T42">CLASSES1:42</a></i>;<br/>
<a NAME="E4:53"/><b>then </b>
 <a href="ordinal1.html#K3">On</a> <font color="Maroon">U1</font> <a href="hidden.html#R2">in</a>  <a href="ordinal1.html#K3">On</a> <font color="Maroon">U3</font>
 
<b>by </b><i><a class="ref" href="ordinal1.html#T19">ORDINAL1:19</a></i>;<br/>
<b>hence </b><a NAME="E5:53"/>
<font color="Maroon">U1</font> <a href="hidden.html#R2">in</a> <font color="Maroon">U3</font>
 <b>by </b><i>, <a class="ref" href="classes1.html#T42">CLASSES1:42</a></i>;<br/>


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