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<b>let </b><font color="Maroon" title="c3">g</font> be   <a href="closure2.html#NM3" title="CLOSURE2:NM.3">SetOp</a> of <font color="Maroon" title="c2">M</font>;<br/>

<b>assume </b><a NAME="E1:61_1_1"/><i><font color="Green" title="E29">A1</font></i>: 
<font color="Maroon" title="c3">g</font> is <a href="closure2.html#V10" title="CLOSURE2:attr.10">topological</a>
 ;<br/>

<b>let </b><font color="Maroon" title="c4">X</font>, <font color="Maroon" title="c5">Y</font> be    <a href="closure2.html#M1" title="CLOSURE2:mode.1">Element</a> of  <a href="closure2.html#K6" title="CLOSURE2:func.6">Bool</a> <font color="Maroon" title="c2">M</font>; <i><font color="Red">:: according to </font></i><a class="ref" href="closure2.html#D13" target="_self" title="CLOSURE2:def.13">CLOSURE2:def 13</a><br/>

<b>assume </b><a NAME="E2:61_1_1"/><i><font color="Green" title="E30">A2</font></i>: 
<font color="Maroon" title="c4">X</font> <a href="pboole.html#R2" title="PBOOLE:pred.2">c=</a> <font color="Maroon" title="c5">Y</font>
 ;<br/>

<span class="p1">(<span class="default"><font color="Maroon" title="c3">g</font> <a href="closure2.html#K7" title="CLOSURE2:func.7">.</a> <font color="Maroon" title="c4">X</font></span>)</span> <a href="pboole.html#K2" title="PBOOLE:func.2">\/</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">g</font> <a href="closure2.html#K7" title="CLOSURE2:func.7">.</a> <font color="Maroon" title="c5">Y</font></span>)</span> = 
<font color="Maroon" title="c3">g</font> <a href="funct_1.html#K1" title="FUNCT_1:func.1">.</a> <span class="p1">(<span class="default"><font color="Maroon" title="c4">X</font> <a href="pboole.html#K2" title="PBOOLE:func.2">\/</a> <font color="Maroon" title="c5">Y</font></span>)</span>
<b>by </b><i><a class="txt" href="closure2.html#E1:61_1_1"><i><font color="Green" title="E29">A1</font></i></a>, <a class="ref" href="closure2.html#D15" target="_self" title="CLOSURE2:def.15">Def15</a></i>
<br/>.= 
<font color="Maroon" title="c3">g</font> <a href="closure2.html#K7" title="CLOSURE2:func.7">.</a> <font color="Maroon" title="c5">Y</font>
<b>by </b><i><a class="txt" href="closure2.html#E2:61_1_1"><i><font color="Green" title="E30">A2</font></i></a>, <a class="ref" href="pboole.html#T24" title="PBOOLE:th.24">PBOOLE:24</a></i>
;<br/>
<b>hence </b><a NAME="E4:61_1_1"/>
<font color="Maroon" title="c3">g</font> <a href="closure2.html#K7" title="CLOSURE2:func.7">.</a> <font color="Maroon" title="c4">X</font> <a href="pboole.html#R2" title="PBOOLE:pred.2">c=</a> <font color="Maroon" title="c3">g</font> <a href="closure2.html#K7" title="CLOSURE2:func.7">.</a> <font color="Maroon" title="c5">Y</font>
 <b>by </b><i><a class="ref" href="pboole.html#T28" title="PBOOLE:th.28">PBOOLE:28</a></i>;<br/>


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