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<b>let </b><font color="Maroon">M1</font> be   <a href="card_1.html#NM1">Cardinal</a>, <font color="Maroon">M2</font> be   <a href="card_1.html#NM1">Cardinal</a>;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:21_1_2"/><i><font color="Green">E49</font></i>: 
(  <a href="card_1.html#K1" target="_self">Card</a> <font color="Maroon">X</font> <a href="card_1.html#NR2" target="_self">&lt;`</a> <font color="Maroon">M1</font> &amp; ( for <font color="Olive">M</font> being  <a href="card_1.html#NM1">Cardinal</a>  st  <a href="card_1.html#K1" target="_self">Card</a> <font color="Maroon">X</font> <a href="card_1.html#NR2" target="_self">&lt;`</a> <font color="Olive">M</font> holds <br/><font color="Maroon">M1</font> <a href="card_1.html#NR1" target="_self">&lt;=`</a> <font color="Olive">M</font> ) )
 <b>and </b><br/><a NAME="E2:21_1_2"/><i><font color="Green">E52</font></i>: 
(  <a href="card_1.html#K1" target="_self">Card</a> <font color="Maroon">X</font> <a href="card_1.html#NR2" target="_self">&lt;`</a> <font color="Maroon">M2</font> &amp; ( for <font color="Olive">M</font> being  <a href="card_1.html#NM1">Cardinal</a>  st  <a href="card_1.html#K1" target="_self">Card</a> <font color="Maroon">X</font> <a href="card_1.html#NR2" target="_self">&lt;`</a> <font color="Olive">M</font> holds <br/><font color="Maroon">M2</font> <a href="card_1.html#NR1" target="_self">&lt;=`</a> <font color="Olive">M</font> ) )
 ;<br/>

<a NAME="E3:21_1_2"/>
( <font color="Maroon">M1</font> <a href="card_1.html#NR1" target="_self">&lt;=`</a> <font color="Maroon">M2</font> &amp; <font color="Maroon">M2</font> <a href="card_1.html#NR1" target="_self">&lt;=`</a> <font color="Maroon">M1</font> )
 
<b>by </b><i>, </i>;<br/>
<b>hence </b><a NAME="E4:21_1_2"/>
<font color="Maroon">M1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">M2</font>
 <b>by </b><i><a class="ref" href="xboole_0.html#D10">XBOOLE_0:def 10</a></i>;<br/>


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