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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E19">Th21</font></span>: <a NAME="T21"><span class="comment"><font color="firebrick">:: WAYBEL19:21</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">T</font>, <font color="Olive" title="b2">S</font> being   <a href="pre_topc.html#NM1" title="PRE_TOPC:NM.1">TopSpace</a>  st  the <a href="struct_0.html#U1" title="STRUCT_0:sel.1">carrier</a> of <font color="Olive" title="b1">T</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  the <a href="struct_0.html#U1" title="STRUCT_0:sel.1">carrier</a> of <font color="Olive" title="b2">S</font> holds <br/> for <font color="Olive" title="b3">R</font> being    <a href="yellow_9.html#M3" title="YELLOW_9:mode.3">Refinement</a> of <font color="Olive" title="b1">T</font>,<font color="Olive" title="b2">S</font><br/>  for <font color="Olive" title="b4">V</font> being   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Olive" title="b1">T</font><br/>  for <font color="Olive" title="b5">W</font> being   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Olive" title="b3">R</font>  st <font color="Olive" title="b5">W</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b4">V</font> &amp; <font color="Olive" title="b4">V</font> is  <a href="pre_topc.html#V4" title="PRE_TOPC:attr.4">closed</a>  holds <br/><font color="Olive" title="b5">W</font> is  <a href="pre_topc.html#V4" title="PRE_TOPC:attr.4">closed</a> </div></div>
