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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E28">Th21</font></span>: <a NAME="T21"><span class="comment"><font color="firebrick">:: PENCIL_1:21</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">S</font> being    <a href="pre_topc.html#L1" title="PRE_TOPC:struct.1">TopStruct</a> <br/>  for <font color="Olive" title="b2">l</font> being   <a href="pencil_1.html#NM1" title="PENCIL_1:NM.1">Block</a> of <font color="Olive" title="b1">S</font><br/>  for <font color="Olive" title="b3">L</font> being   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Olive" title="b1">S</font>  st <font color="Olive" title="b3">L</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b2">l</font> holds <br/><font color="Olive" title="b3">L</font> is  <a href="pencil_1.html#V2" title="PENCIL_1:attr.2">strong</a> </div></div>
