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<a NAME="E1:25_1_1"/>
<font color="Maroon">S</font> <a href="msafree3.html#K2" target="_self">variables_in</a> <font color="Maroon">t</font> <a href="pboole.html#R2">c=</a> <font color="Maroon">X</font>
 
<b>by </b><i/>;<br/>
<a NAME="E2:25_1_1"/><b>then </b>
<font color="Maroon">X</font> <a href="pboole.html#K3">/\</a> <span class="p1">(<span class="default"><font color="Maroon">S</font> <a href="msafree3.html#K2" target="_self">variables_in</a> <font color="Maroon">t</font></span>)</span> <a href="pboole.html#R6">=</a> <font color="Maroon">S</font> <a href="msafree3.html#K2" target="_self">variables_in</a> <font color="Maroon">t</font>
 
<b>by </b><i><a class="ref" href="pboole.html#T25">PBOOLE:25</a></i>;<br/>
<a NAME="E3:25_1_1"/><b>then </b>
<font color="Maroon">S</font> <a href="msafree3.html#K2" target="_self">variables_in</a> <font color="Maroon">t</font> <a href="pboole.html#R6">=</a> <font color="Maroon">X</font> <a href="msafree3.html#K3" target="_self">variables_in</a> <font color="Maroon">t</font>
 
;<br/>
<b>hence </b><a NAME="E4:25_1_1"/>
<font color="Maroon">S</font> <a href="msafree3.html#K2" target="_self">variables_in</a> <font color="Maroon">t</font> is    <a href="pboole.html#M4">ManySortedSubset</a> of <font color="Maroon">X</font>
 ;<br/>


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