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<b>thus </b><a NAME="E1:9_1_1"/>
( ( for <font color="Olive">x</font> being   <a href="hidden.html#M1">set</a>   st <font color="Olive">x</font> <a href="hidden.html#R2">in</a>  <a href="xboole_0.html#K1">{}</a>  holds <br/><font color="Olive">x</font> is   <a href="finseq_1.html#NM1">FinSequence</a> ) &amp; ( for <font color="Olive">a</font>, <font color="Olive">b</font> being  <a href="finseq_1.html#NM1">FinSequence</a>  st <font color="Olive">a</font> <a href="hidden.html#R2">in</a>  <a href="xboole_0.html#K1">{}</a>  &amp; <font color="Olive">b</font> <a href="hidden.html#R2">in</a>  <a href="xboole_0.html#K1">{}</a>  holds <br/> <a href="finseq_1.html#K3">len</a> <font color="Olive">a</font> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K3">len</a> <font color="Olive">b</font> ) )
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="margrel1.html#D1" target="_self">MARGREL1:def 1</a><br/>


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