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<div><span class="kw">theorem </span><a NAME="T28"><span class="comment"><font color="firebrick">:: SETFAM_1:28</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">SFX</font>, <font color="Olive" title="b2">SFY</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>  holds   <a href="tarski.html#K3" title="TARSKI:func.3">union</a> <span class="p1">(<span class="default"><a href="setfam_1.html#K3" title="SETFAM_1:func.3">INTERSECTION</a> (<font color="Olive" title="b1">SFX</font>,<font color="Olive" title="b2">SFY</font>)</span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="tarski.html#K3" title="TARSKI:func.3">union</a> <font color="Olive" title="b1">SFX</font></span>)</span> <a href="xboole_0.html#K3" title="XBOOLE_0:func.3">/\</a> <span class="p1">(<span class="default"><a href="tarski.html#K3" title="TARSKI:func.3">union</a> <font color="Olive" title="b2">SFY</font></span>)</span></div></div>
