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<b>let </b><font color="Maroon">c<sub>1</sub></font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be    <a href="pboole.html#M1" target="_self">ManySortedSet</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>





<b>assume </b><a NAME="E1:33"/><i><font color="Green">E27</font></i>: 
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R2" target="_self">c=</a> <font color="Maroon">c<sub>3</sub></font>
 ;<br/>

<b>thus </b><a NAME="E2:33"/>
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#K3" target="_self">/\</a> <font color="Maroon">c<sub>3</sub></font> <a href="pboole.html#R2" target="_self">c=</a> <font color="Maroon">c<sub>2</sub></font>
 <b>by </b><i><a class="ref" href="pboole.html#T17" target="_self">Th17</a></i>; <i><font color="Red">:: according to </font></i><a class="ref" href="pboole.html#D13" target="_self">PBOOLE:def 13</a><br/>

<b>thus </b><a NAME="E3:33"/>
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R2" target="_self">c=</a> <font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#K3" target="_self">/\</a> <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="txt" href="pboole.html#E1:33"><i><font color="Green">E27</font></i></a>, <a class="ref" href="pboole.html#T19" target="_self">Th19</a></i>;<br/>

<b>thus </b><a NAME="E4:33"/>
<font color="Maroon">c<sub>3</sub></font> <a href="pboole.html#K3" target="_self">/\</a> <font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R2" target="_self">c=</a> <font color="Maroon">c<sub>2</sub></font>
 <b>by </b><i><a class="ref" href="pboole.html#T17" target="_self">Th17</a></i>; <i><font color="Red">:: according to </font></i><a class="ref" href="pboole.html#D13" target="_self">PBOOLE:def 13</a><br/>

<b>thus </b><a NAME="E5:33"/>
<font color="Maroon">c<sub>2</sub></font> <a href="pboole.html#R2" target="_self">c=</a> <font color="Maroon">c<sub>3</sub></font> <a href="pboole.html#K3" target="_self">/\</a> <font color="Maroon">c<sub>2</sub></font>
 <b>by </b><i><a class="txt" href="pboole.html#E1:33"><i><font color="Green">E27</font></i></a>, <a class="ref" href="pboole.html#T19" target="_self">Th19</a></i>;<br/>


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