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<div><span class="kw">theorem </span><a NAME="T40"><span class="comment"><font color="firebrick">:: NAT_D:40</font></span><br/></a><div class="add"> for <font color="Olive" title="b1">n</font> being   <a href="ordinal1.html#V7" title="ORDINAL1:attr.7">natural</a>   <a href="ordinal1.html#NM1" title="ORDINAL1:NM.1">Number</a>  holds  <font color="Olive" title="b1">n</font> <a href="xreal_0.html#K1" title="XREAL_0:func.1">-'</a> <a href="numbers.html#K5" title="NUMBERS:func.5">0</a> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b1">n</font></div></div>
