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<b>consider </b><font color="Maroon">f</font> being  <a href="relat_1.html#V2">V2</a>  <a href="pboole.html#M1">ManySortedSet</a> of <font color="Maroon">A</font>;<br/>
<b>take </b>
<font color="Maroon">f</font>
;<br/>

<b>consider </b><font color="Maroon">a</font> being    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">A</font>;<br/>
<b>take </b>
<font color="Maroon">a</font>
; <i><font color="Red">:: according to </font></i><a class="ref" href="pboole.html#D15">PBOOLE:def 15</a><br/>

<b>thus </b><a NAME="E3:1_1_1"/>
( <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">A</font> &amp; not <font color="Maroon">f</font> <a href="funct_1.html#K1">.</a> <font color="Maroon">a</font> is <a href="xboole_0.html#V1">empty</a> )
 ;<br/>


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