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<div><span class="kw">theorem </span><a NAME="T12"><span class="comment"><font color="firebrick">:: RELSET_1:12</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   <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a>  is   <a href="relset_1.html#NM1" title="RELSET_1:NM.1">Relation</a> of <font color="Olive" title="b1">X</font>,<font color="Olive" title="b2">Y</font> <span class="kw">by</span> <span class="lab"><a class="ref" href="xboole_1.html#T2" onmouseover="rs('xboole_1/T2')" onmouseout="rh()">XBOOLE_1:2</a></span>;<br/></div></div>
