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<b>let </b><font color="Maroon" title="c1">G</font> be   <a href="group_1.html#NM1" title="GROUP_1:NM.1">Group</a>;<br/><b>let </b><font color="Maroon" title="c2">A</font> be   <a href="struct_0.html#NM2" title="STRUCT_0:NM.2">Subset</a> of <font color="Maroon" title="c1">G</font>;<br/>



<a NAME="E1:10"/><i><font color="Green" title="E7">A1</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> </span>)</span> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a>  <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">{<span class="default"> <span class="p2">(<span class="default"><font color="Olive" title="b1">g</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a> </span>)</span> where <font color="Olive" title="b1">g</font> is   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font> : <font color="Olive" title="b1">g</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a>  </span>}</span> 
 
<b>by </b><i><a class="ref" href="group_2.html#D1" title="GROUP_2:def.1">GROUP_2:def 1</a></i>;<br/>
<a NAME="E2:10"/><i><font color="Green" title="E8">A2</font></i>: 
<font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a>  <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <span class="p1">{<span class="default"> <span class="p2">(<span class="default"><font color="Olive" title="b1">g</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a> </span>)</span> where <font color="Olive" title="b1">g</font> is   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font> : <font color="Olive" title="b1">g</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font> </span>}</span> 
 
<b>by </b><i><a class="ref" href="group_2.html#D1" title="GROUP_2:def.1">GROUP_2:def 1</a></i>;<br/>
<div><b>hereby </b> <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3" title="TARSKI:def.3">TARSKI:def 3</a>,<a class="ref" href="xboole_0.html#D10" title="XBOOLE_0:def.10">XBOOLE_0:def 10</a>
<div class="add"><b>let </b><font color="Maroon" title="c3">x</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>assume </b><a NAME="E1:10_1"/>
<font color="Maroon" title="c3">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> </span>)</span> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> 
 ;<br/><b>then consider </b><font color="Maroon" title="c4">g</font> being   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font><b> such that </b><br/><a NAME="E3:10_1"/><i><font color="Green" title="E9">A3</font></i>: 
( <font color="Maroon" title="c3">x</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c4">g</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a>  &amp; <font color="Maroon" title="c4">g</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a>  )
 <b>by </b><i><a class="txt" href="topgrp_1.html#E1:10"><i><font color="Green" title="E7">A1</font></i></a></i>;<br/><b>consider </b><font color="Maroon" title="c5">h</font> being   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font><b> such that </b><br/><a NAME="E5:10_1"/><i><font color="Green" title="E10">A4</font></i>: 
( <font color="Maroon" title="c4">g</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c5">h</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a>  &amp; <font color="Maroon" title="c5">h</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font> )
 <b>by </b><i><a class="txt" href="topgrp_1.html#E2:10"><i><font color="Green" title="E8">A2</font></i></a>, <a class="txt" href="topgrp_1.html#E3:10_1"><i><font color="Green" title="E9">A3</font></i></a></i>;<br/><b>thus </b><a NAME="E6:10_1"/>
<font color="Maroon" title="c3">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font>
 <b>by </b><i><a class="txt" href="topgrp_1.html#E3:10_1"><i><font color="Green" title="E9">A3</font></i></a>, <a class="txt" href="topgrp_1.html#E5:10_1"><i><font color="Green" title="E10">A4</font></i></a>, <a class="ref" href="group_1.html#T19" title="GROUP_1:th.19">GROUP_1:19</a></i>;<br/></div>
<b>end;</b></div>

<b>let </b><font color="Maroon" title="c3">x</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="tarski.html#D3" title="TARSKI:def.3">TARSKI:def 3</a><br/>

<b>assume </b><a NAME="E4:10"/><i><font color="Green" title="E9">A5</font></i>: 
<font color="Maroon" title="c3">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font>
 ;<br/>

<b>then reconsider </b><font color="Maroon" title="c4">g</font> = <font color="Maroon" title="c3">x</font> as   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">G</font> ;<br/>
<a NAME="E6:10"/>
<font color="Maroon" title="c4">g</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a>  <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> 
 
<b>by </b><i><a class="txt" href="topgrp_1.html#E2:10"><i><font color="Green" title="E8">A2</font></i></a>, <a class="txt" href="topgrp_1.html#E4:10"><i><font color="Green" title="E9">A5</font></i></a></i>;<br/>
<a NAME="E7:10"/><b>then </b>
<span class="p1">(<span class="default"><font color="Maroon" title="c4">g</font> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a> </span>)</span> <a href="group_1.html#K3" title="GROUP_1:func.3">"</a>  <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> </span>)</span> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> 
 
<b>by </b><i><a class="txt" href="topgrp_1.html#E1:10"><i><font color="Green" title="E7">A1</font></i></a></i>;<br/>
<b>hence </b><a NAME="E8:10"/>
<font color="Maroon" title="c3">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">(<span class="default"><font color="Maroon" title="c2">A</font> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> </span>)</span> <a href="group_2.html#K1" title="GROUP_2:func.1">"</a> 
 <b>by </b><i><a class="ref" href="group_1.html#T19" title="GROUP_1:th.19">GROUP_1:19</a></i>;<br/>


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