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<b>let </b><font color="Maroon" title="c1">k</font>, <font color="Maroon" title="c2">n</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="numbers.html#K5" title="NUMBERS:func.5">NAT</a> ;<br/>



<b>assume </b><a NAME="E1:8"/>
<font color="Maroon" title="c1">k</font> <a href="xxreal_0.html#R1" title="XXREAL_0:pred.1">&lt;=</a> <font color="Maroon" title="c2">n</font>
 ;<br/>

<a NAME="E2:8"/><b>then </b>
 <a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c1">k</font> <a href="tarski.html#R1" title="TARSKI:pred.1">c=</a>  <a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c2">n</font>
 
<b>by </b><i><a class="ref" href="algseq_1.html#T13" target="_self" title="ALGSEQ_1:th.13">Th13</a></i>;<br/>
<b>hence </b><a NAME="E3:8"/>
(  <a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c1">k</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c1">k</font></span>)</span> <a href="subset_1.html#K9" title="SUBSET_1:func.9">/\</a> <span class="p1">(<span class="default"><a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c2">n</font></span>)</span> &amp;  <a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c1">k</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">(<span class="default"><a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c2">n</font></span>)</span> <a href="subset_1.html#K9" title="SUBSET_1:func.9">/\</a> <span class="p1">(<span class="default"><a href="algseq_1.html#K2" title="ALGSEQ_1:func.2">PSeg</a> <font color="Maroon" title="c1">k</font></span>)</span> )
 <b>by </b><i><a class="ref" href="xboole_1.html#T28" title="XBOOLE_1:th.28">XBOOLE_1:28</a></i>;<br/>


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