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<b>let </b><font color="Maroon" title="c1">X</font> be  non <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>  <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c2">PX</font> be    <a href="eqrel_1.html#M1" title="EQREL_1:mode.1">a_partition</a> of <font color="Maroon" title="c1">X</font>;<br/><b>let </b><font color="Maroon" title="c3">Pi</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/>





<b>assume </b><a NAME="E1:7"/>
<font color="Maroon" title="c3">Pi</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">PX</font>
 ;<br/>

<b>then reconsider </b><font color="Maroon" title="c4">Pi</font> = <font color="Maroon" title="c3">Pi</font> as    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of <font color="Maroon" title="c2">PX</font> ;<br/>
<a NAME="E3:7"/><i><font color="Green" title="E5">A1</font></i>: 
<font color="Maroon" title="c4">Pi</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="ref" href="eqrel_1.html#D6" title="EQREL_1:def.6">EQREL_1:def 6</a></i>;<br/>
<b>consider </b><font color="Maroon" title="c5">q</font> being    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c4">Pi</font>;<br/>
<a NAME="E5:7"/>
<font color="Maroon" title="c5">q</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c4">Pi</font>
 
<b>by </b><i><a class="txt" href="fsm_1.html#E3:7"><i><font color="Green" title="E5">A1</font></i></a></i>;<br/>
<b>then reconsider </b><font color="Maroon" title="c6">q</font> = <font color="Maroon" title="c5">q</font> as    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of <font color="Maroon" title="c1">X</font> ;<br/>
<b>take </b>
<font color="Maroon" title="c6">q</font>
;<br/>

<b>thus </b><a NAME="E7:7"/>
<font color="Maroon" title="c6">q</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">Pi</font>
 <b>by </b><i><a class="txt" href="fsm_1.html#E3:7"><i><font color="Green" title="E5">A1</font></i></a></i>;<br/>


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