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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E20">Th19</font></span>: <a NAME="T19"><span class="comment"><font color="firebrick">:: SCMYCIEL:19</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font>, <font color="Olive" title="b2">x</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>   st  <a href="card_1.html#K1" title="CARD_1:func.1">card</a> <span class="p1">(<span class="default"><a href="tarski.html#K3" title="TARSKI:func.3">union</a> <font color="Olive" title="b1">X</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> 1 holds <br/><font color="Olive" title="b1">X</font> is  <a href="scmyciel.html#V2" title="SCMYCIEL:attr.2">pairfree</a> </div></div>
