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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E7">Th03</font></span>: <a NAME="T13"><span class="comment"><font color="firebrick">:: CARDFIL2:13</font></span><br/></a><div class="add"> 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">F</font> being    <a href="card_fil.html#M1" title="CARD_FIL:mode.1">Filter</a> of <font color="Olive" title="b1">X</font> holds  <font color="Olive" title="b2">F</font> is   <a href="cardfil2.html#NM1" title="CARDFIL2:NM.1">basis</a> of <font color="Olive" title="b2">F</font></div></div>
