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<b>let </b><font color="Maroon" title="c1">a</font> be   <a href="card_5.html#NM1" title="CARD_5:NM.1">Aleph</a>;<br/>

<a NAME="E1:36"/><i><font color="Green" title="E28">A1</font></i>: 
( <font color="Maroon" title="c1">a</font> <a href="ordinal2.html#R2" title="ORDINAL2:pred.2">is_cofinal_with</a>  <a href="card_5.html#K1" title="CARD_5:func.1">cf</a> <font color="Maroon" title="c1">a</font> &amp; <font color="Maroon" title="c1">a</font> <a href="ordinal1.html#NR2" title="ORDINAL1:NR.2">is_limit_ordinal</a>  )
 
<b>by </b><i><a class="ref" href="card_5.html#D2" target="_self" title="CARD_5:def.2">Def2</a>, <a class="ref" href="card_4.html#T32" title="CARD_4:th.32">CARD_4:32</a></i>;<br/>
<a NAME="E2:36"/><b>then </b><i><font color="Green" title="E29">A2</font></i>: 
 <a href="card_5.html#K1" title="CARD_5:func.1">cf</a> <font color="Maroon" title="c1">a</font> <a href="ordinal1.html#NR2" title="ORDINAL1:NR.2">is_limit_ordinal</a> 
 
<b>by </b><i><a class="ref" href="ordinal4.html#T40" title="ORDINAL4:th.40">ORDINAL4:40</a></i>;<br/>
<a NAME="E3:36"/>
 <a href="card_5.html#K1" title="CARD_5:func.1">cf</a> <font color="Maroon" title="c1">a</font> <a href="hidden.html#NR2" title="HIDDEN:NR.2">&lt;&gt;</a>  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a> 
 
<b>by </b><i><a class="txt" href="card_5.html#E1:36"><i><font color="Green" title="E28">A1</font></i></a>, <a class="ref" href="ordinal2.html#T68" title="ORDINAL2:th.68">ORDINAL2:68</a></i>;<br/>
<a NAME="E4:36"/><b>then </b>
 <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a>  <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="card_5.html#K1" title="CARD_5:func.1">cf</a> <font color="Maroon" title="c1">a</font>
 
<b>by </b><i><a class="ref" href="ordinal3.html#T10" title="ORDINAL3:th.10">ORDINAL3:10</a></i>;<br/>
<b>hence </b><a NAME="E5:36"/>
 <a href="card_1.html#K3" title="CARD_1:func.3">alef</a> <a href="numbers.html#K6" title="NUMBERS:func.6">0</a>  <a href="card_1.html#NR1" title="CARD_1:NR.1">&lt;=`</a>  <a href="card_5.html#K1" title="CARD_5:func.1">cf</a> <font color="Maroon" title="c1">a</font>
 <b>by </b><i><a class="txt" href="card_5.html#E2:36"><i><font color="Green" title="E29">A2</font></i></a>, <a class="ref" href="card_1.html#T83" title="CARD_1:th.83">CARD_1:83</a>, <a class="ref" href="ordinal1.html#D12" title="ORDINAL1:def.12">ORDINAL1:def 12</a></i>;<br/>


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