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<div><span class="kw">theorem </span><a NAME="T23"><span class="comment"><font color="firebrick">:: MBOOLEAN:23</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">x</font> being    <a href="hidden.html#M1" title="HIDDEN:mode.1">object</a> <br/>  for <font color="Olive" title="b2">I</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>  holds   <a href="mboolean.html#K2" title="MBOOLEAN:func.2">union</a> <span class="p1">(<span class="default"><font color="Olive" title="b2">I</font> <a href="funcop_1.html#K7" title="FUNCOP_1:func.7">--&gt;</a> <span class="p2"><a href="tarski.html#K1" title="TARSKI:func.1">{</a><span class="default"><font color="Olive" title="b1">x</font></span><a href="tarski.html#K1" title="TARSKI:func.1">}</a></span></span>)</span> <a href="pboole.html#R6" title="PBOOLE:pred.6">=</a> <font color="Olive" title="b2">I</font> <a href="funcop_1.html#K7" title="FUNCOP_1:func.7">--&gt;</a> <font color="Olive" title="b1">x</font></div></div>
