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<div><span class="kw">theorem </span><a NAME="T37"><span class="comment"><font color="firebrick">:: XBOOLE_1:37</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font>, <font color="Olive" title="b2">Y</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>  holds <br/> ( <font color="Olive" title="b1">X</font> <a href="xboole_0.html#K4" title="XBOOLE_0:func.4">\</a> <font color="Olive" title="b2">Y</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a>  iff <font color="Olive" title="b1">X</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Olive" title="b2">Y</font> ) <span class="kw">by</span> <span class="lab"><a class="txt" href="xboole_1.html#E32"><span class="lab"><font color="Green" title="E14">Lm1</font></span></a></span>;<br/></div></div>
