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<b>let </b><font color="Maroon" title="c1">I</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c2">A</font> be    <a href="pboole.html#M1" title="PBOOLE:mode.1">ManySortedSet</a> of <font color="Maroon" title="c1">I</font>;<br/>



<a NAME="E1:16"/>
 <a href="msualg_3.html#K2" title="MSUALG_3:func.2">id</a> <font color="Maroon" title="c2">A</font> is <a href="msualg_3.html#V2" title="MSUALG_3:attr.2">"onto"</a>
 
<b>by </b><i><a class="ref" href="autalg_1.html#T24" title="AUTALG_1:th.24">AUTALG_1:24</a></i>;<br/>
<a NAME="E2:16"/><b>then </b><i><font color="Green" title="E8">A1</font></i>: 
 <a href="extens_1.html#K2" title="EXTENS_1:func.2">rngs</a> <span class="p1">(<span class="default"><a href="msualg_3.html#K2" title="MSUALG_3:func.2">id</a> <font color="Maroon" title="c2">A</font></span>)</span> <a href="pboole.html#R6" title="PBOOLE:pred.6">=</a> <font color="Maroon" title="c2">A</font>
 
<b>by </b><i><a class="ref" href="extens_1.html#T13" title="EXTENS_1:th.13">EXTENS_1:13</a></i>;<br/>
<a NAME="E3:16"/>
 <a href="extens_1.html#K1" title="EXTENS_1:func.1">doms</a> <span class="p1">(<span class="default"><a href="msualg_3.html#K2" title="MSUALG_3:func.2">id</a> <font color="Maroon" title="c2">A</font></span>)</span> <a href="pboole.html#R6" title="PBOOLE:pred.6">=</a> <font color="Maroon" title="c2">A</font>
 
<b>by </b><i><a class="ref" href="mssubfam.html#T17" title="MSSUBFAM:th.17">MSSUBFAM:17</a></i>;<br/>
<b>hence </b><a NAME="E4:16"/>
<span class="p1">(<span class="default"><a href="msualg_3.html#K2" title="MSUALG_3:func.2">id</a> <font color="Maroon" title="c2">A</font></span>)</span> <a href="pboole.html#K13" title="PBOOLE:func.13">.:.:</a> <font color="Maroon" title="c2">A</font> <a href="pboole.html#R6" title="PBOOLE:pred.6">=</a> <font color="Maroon" title="c2">A</font>
 <b>by </b><i><a class="txt" href="equation.html#E2:16"><i><font color="Green" title="E8">A1</font></i></a>, <a class="ref" href="equation.html#T14" target="_self" title="EQUATION:th.14">Th14</a></i>;<br/>


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