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<div><span class="kw">theorem </span><a NAME="T31"><span class="comment"><font color="firebrick">:: CARD_3:31</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">F</font> being   <a href="card_3.html#NM1" title="CARD_3:NM.1">Cardinal-Function</a> holds <br/> (  <a href="xboole_0.html#K1" title="XBOOLE_0:func.1">{}</a>  <a href="tarski.html#R2" title="TARSKI:pred.2">in</a>  <a href="xtuple_0.html#K10" title="XTUPLE_0:func.10">rng</a> <font color="Olive" title="b1">F</font> iff  <a href="card_3.html#K7" title="CARD_3:func.7">Product</a> <font color="Olive" title="b1">F</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="ordinal1.html#K5" title="ORDINAL1:func.5">0</a>  )</div></div>
