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<b>let </b><font color="Maroon">c<sub>1</sub></font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be    <a href="pboole.html#M1">ManySortedSet</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>





<b>assume </b><a NAME="E1:59"/>
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R2">c=</a> <font color="Maroon">c<sub>3</sub></font>
 ;<br/>

<a NAME="E2:59"/><b>then </b>
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R1">in</a>  <a href="mssubfam.html#K3" target="_self">bool</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="ref" href="mboolean.html#T19">MBOOLEAN:19</a></i>;<br/>
<a NAME="E3:59"/><b>then </b>
<span class="p1"><a href="pzfmisc1.html#K1">{</a><span class="default"><font color="Maroon">c<sub>2</sub></font></span><a href="pzfmisc1.html#K1">}</a></span> <a href="pboole.html#R2">c=</a>  <a href="mssubfam.html#K3" target="_self">bool</a> <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="ref" href="pzfmisc1.html#T36">PZFMISC1:36</a></i>;<br/>
<b>hence </b><a NAME="E4:59"/>
<span class="p1"><a href="pzfmisc1.html#K1">{</a><span class="default"><font color="Maroon">c<sub>2</sub></font></span><a href="pzfmisc1.html#K1">}</a></span> is   <a href="mssubfam.html#NM1">MSSubsetFamily</a> of <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="ref" href="pboole.html#D23">PBOOLE:def 23</a></i>;<br/>


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