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<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="group_1.html#NM1">Group</a>;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be  <a href="group_1.html#V1">strict</a>  <a href="group_2.html#M1">Subgroup</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>



<a NAME="E1:79"/>
( ( <font color="Maroon">c<sub>2</sub></font> <a href="group_4.html#K8" target="_self">"\/"</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font> implies <font color="Maroon">c<sub>2</sub></font> is    <a href="group_2.html#M1">Subgroup</a> of <font color="Maroon">c<sub>3</sub></font> ) &amp; ( <font color="Maroon">c<sub>2</sub></font> is    <a href="group_2.html#M1">Subgroup</a> of <font color="Maroon">c<sub>3</sub></font> implies <font color="Maroon">c<sub>2</sub></font> <a href="group_4.html#K8" target="_self">"\/"</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font> ) &amp; ( <font color="Maroon">c<sub>2</sub></font> <a href="group_2.html#K9">/\</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font> implies <font color="Maroon">c<sub>2</sub></font> is    <a href="group_2.html#M1">Subgroup</a> of <font color="Maroon">c<sub>3</sub></font> ) &amp; ( <font color="Maroon">c<sub>2</sub></font> is    <a href="group_2.html#M1">Subgroup</a> of <font color="Maroon">c<sub>3</sub></font> implies <font color="Maroon">c<sub>2</sub></font> <a href="group_2.html#K9">/\</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font> ) )
 
<b>by </b><i><a class="ref" href="group_4.html#T79" target="_self">Th79</a>, <a class="ref" href="group_2.html#T107">GROUP_2:107</a></i>;<br/>
<b>hence </b><a NAME="E2:79"/>
( <font color="Maroon">c<sub>2</sub></font> <a href="group_4.html#K8" target="_self">"\/"</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font> iff <font color="Maroon">c<sub>2</sub></font> <a href="group_2.html#K9">/\</a> <font color="Maroon">c<sub>3</sub></font> <a href="group_2.html#R1">=</a> <font color="Maroon">c<sub>2</sub></font> )
 ;<br/>


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