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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E53">Th89</font></span>: <a NAME="T87"><span class="comment"><font color="firebrick">:: CLASSES5:87</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">U</font> being   <a href="classes2.html#NM1" title="CLASSES2:NM.1">Universe</a><br/>  for <font color="Olive" title="b2">C</font> being   <a href="classes5.html#NM3" title="CLASSES5:NM.3">CategorySet</a> holds <br/> ( <font color="Olive" title="b2">C</font> is <font color="Olive" title="b1">U</font> <a href="classes5.html#V2" title="CLASSES5:attr.2">-set</a>  iff  <a href="classes5.html#K19" title="CLASSES5:func.19">SetToCat</a> <font color="Olive" title="b2">C</font> is <font color="Olive" title="b1">U</font> <a href="classes5.html#V7" title="CLASSES5:attr.7">-element</a>  )</div></div>
