<?xml version="1.0"?>
<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E7">Th7</font></span>: <a NAME="T7"><span class="comment"><font color="firebrick">:: CARD_4:7</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">X</font>, <font color="Olive" title="b2">Y</font> being    <a href="hidden.html#M2" title="HIDDEN:mode.2">set</a>   st <font color="Olive" title="b1">X</font> is  <a href="card_3.html#V4" title="CARD_3:attr.4">countable</a>  &amp; <font color="Olive" title="b2">Y</font> is  <a href="card_3.html#V4" title="CARD_3:attr.4">countable</a>  holds <br/><span class="p1"><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">[:</a><span class="default"><font color="Olive" title="b1">X</font>,<font color="Olive" title="b2">Y</font></span><a href="zfmisc_1.html#K2" title="ZFMISC_1:func.2">:]</a></span> is  <a href="card_3.html#V4" title="CARD_3:attr.4">countable</a> </div></div>
