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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E3">Th4</font></span>: <a NAME="T4"><span class="comment"><font color="firebrick">:: TOPS_1:4</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">GX</font> being    <a href="pre_topc.html#L1" title="PRE_TOPC:struct.1">TopStruct</a> <br/>  for <font color="Olive" title="b2">R</font> being   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Olive" title="b1">GX</font> holds <br/> ( <font color="Olive" title="b2">R</font> is  <a href="pre_topc.html#V3" title="PRE_TOPC:attr.3">open</a>  iff <font color="Olive" title="b2">R</font> <a href="subset_1.html#K3" title="SUBSET_1:func.3">`</a>  is  <a href="pre_topc.html#V4" title="PRE_TOPC:attr.4">closed</a>  )</div></div>
