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<div><span class="kw">theorem </span><span class="lab"><font color="Green" title="E6">Th21</font></span>: <a NAME="T21"><span class="comment"><font color="firebrick">:: NAT_2:21</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">n</font> being   <a href="ordinal1.html#NM6" title="ORDINAL1:NM.6">Nat</a> holds <br/> ( <font color="Olive" title="b1">n</font> is  <a href="abian.html#V1" title="ABIAN:attr.1">even</a>  iff <font color="Olive" title="b1">n</font> <a href="nat_d.html#K4" title="NAT_D:func.4">mod</a> 2 <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="numbers.html#K5" title="NUMBERS:func.5">0</a>  )</div></div>
