<?xml version="1.0"?>
<div><span class="kw">theorem </span><a NAME="T7"><span class="comment"><font color="firebrick">:: RPR_1:7</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">E</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>   ex <font color="Olive" title="b2">e</font> being   <a href="card_1.html#NM2" title="CARD_1:NM.2">Singleton</a> of <font color="Olive" title="b1">E</font> st <font color="Olive" title="b2">e</font> is   <a href="card_1.html#NM2" title="CARD_1:NM.2">Singleton</a> of <font color="Olive" title="b1">E</font></div></div>
