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<b>let </b><font color="Maroon" title="c1">G</font> be  <a href="topgrp_1.html#V4" title="TOPGRP_1:attr.4">BinContinuous</a> <a href="topgrp_1.html#NM4" title="TOPGRP_1:NM.4">TopGroup</a>;<br/><b>let </b><font color="Maroon" title="c2">O</font> be  <a href="pre_topc.html#V3" title="PRE_TOPC:attr.3">open</a> <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Maroon" title="c1">G</font>;<br/><b>let </b><font color="Maroon" title="c3">a</font> be   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font>;<br/>





<a NAME="E1:95"/>
<font color="Maroon" title="c3">a</font> <a href="group_2.html#K3" title="GROUP_2:func.3">*</a> <font color="Maroon" title="c2">O</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><font color="Maroon" title="c3">a</font> <a href="topgrp_1.html#K7" title="TOPGRP_1:func.7">*</a> </span>)</span> <a href="relset_1.html#K10" title="RELSET_1:func.10">.:</a> <font color="Maroon" title="c2">O</font>
 
<b>by </b><i><a class="ref" href="topgrp_1.html#T16" target="_self" title="TOPGRP_1:th.16">Th16</a></i>;<br/>
<b>hence </b><a NAME="E2:95"/>
<font color="Maroon" title="c3">a</font> <a href="group_2.html#K3" title="GROUP_2:func.3">*</a> <font color="Maroon" title="c2">O</font> is <a href="pre_topc.html#V3" title="PRE_TOPC:attr.3">open</a>
 <b>by </b><i><a class="ref" href="topgrp_1.html#T25" target="_self" title="TOPGRP_1:th.25">Th25</a></i>;<br/>


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