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<b>let </b><font color="Maroon">c<sub>1</sub></font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font> be   <a href="eqrel_1.html#NM2">Equivalence_Relation</a> of <font color="Maroon">c<sub>1</sub></font>;<br/><b>let </b><font color="Maroon">c<sub>3</sub></font> be    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">c<sub>1</sub></font>;<br/><b>let </b><font color="Maroon">c<sub>4</sub></font> be    <a href="filter_1.html#M2" target="_self">BinOp</a> of <font color="Maroon">c<sub>1</sub></font>,<font color="Maroon">c<sub>2</sub></font>;<br/>







<b>assume </b><a NAME="E1:16"/>
( <font color="Maroon">c<sub>3</sub></font> <a href="binop_1.html#R1">is_a_left_unity_wrt</a> <font color="Maroon">c<sub>4</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="binop_1.html#R2">is_a_right_unity_wrt</a> <font color="Maroon">c<sub>4</sub></font> )
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="binop_1.html#D7">BINOP_1:def 7</a><br/>

<b>hence </b><a NAME="E2:16"/>
(  <a href="eqrel_1.html#K10">EqClass</a> <font color="Maroon">c<sub>2</sub></font>,<font color="Maroon">c<sub>3</sub></font> <a href="binop_1.html#R1">is_a_left_unity_wrt</a> <font color="Maroon">c<sub>4</sub></font> <a href="filter_1.html#K3" target="_self">/\/</a> <font color="Maroon">c<sub>2</sub></font> &amp;  <a href="eqrel_1.html#K10">EqClass</a> <font color="Maroon">c<sub>2</sub></font>,<font color="Maroon">c<sub>3</sub></font> <a href="binop_1.html#R2">is_a_right_unity_wrt</a> <font color="Maroon">c<sub>4</sub></font> <a href="filter_1.html#K3" target="_self">/\/</a> <font color="Maroon">c<sub>2</sub></font> )
 <b>by </b><i><a class="ref" href="filter_1.html#T6" target="_self">Th6</a>, <a class="ref" href="filter_1.html#T7" target="_self">Th7</a></i>; <i><font color="Red">:: according to </font></i><a class="ref" href="binop_1.html#D7">BINOP_1:def 7</a><br/>


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