<?xml version="1.0"?>
<div><span class="kw">theorem </span><a NAME="T1"><span class="comment"><font color="firebrick">:: SIMPLEX0:1</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">Y</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>  holds <br/> ( <font color="Olive" title="b1">Y</font> is  <a href="classes1.html#V1" title="CLASSES1:attr.1">subset-closed</a>  iff  for <font color="Olive" title="b2">X</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>   st <font color="Olive" title="b2">X</font> <a href="tarski.html#R2" title="TARSKI:pred.2">in</a> <font color="Olive" title="b1">Y</font> holds <br/> <a href="setfam_1.html#K9" title="SETFAM_1:func.9">bool</a> <font color="Olive" title="b2">X</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a> <font color="Olive" title="b1">Y</font> )</div></div>
