<?xml version="1.0"?>
<div>:: <span class="kw">deftheorem </span>   defines <a href="classes5.html#V2" title="CLASSES5:attr.2">-set</a> <a onclick="hs(this)" href="javascript:()">CLASSES5:def 8 : <br/></a><span> for <font color="Olive" title="b1">X</font> being   non  <a href="xboole_0.html#V1" title="XBOOLE_0:attr.1">empty</a>   <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a> <br/>  for <font color="Olive" title="b2">x</font> being    <a href="hidden.html#M1" title="HIDDEN:mode.1">object</a>  holds <br/> ( <font color="Olive" title="b2">x</font> is <font color="Olive" title="b1">X</font> <a href="classes5.html#V2" title="CLASSES5:attr.2">-set</a>  iff <font color="Olive" title="b2">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Olive" title="b1">X</font> );<br/></span></div>
