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<b>let </b><font color="Maroon">c<sub>1</sub></font> be  non <a href="struct_0.html#V3">empty</a>  <a href="robbins1.html#L3" target="_self">OrthoLattStr</a> ;<br/>

<b>assume </b><a NAME="E1:108_1_1"/><i><font color="Green">E65</font></i>: 
( <font color="Maroon">c<sub>1</sub></font> is <a href="lattices.html#V5">join-associative</a> &amp; <font color="Maroon">c<sub>1</sub></font> is <a href="lattices.html#V4">join-commutative</a> &amp; <font color="Maroon">c<sub>1</sub></font> is <a href="robbins1.html#V9" target="_self">de_Morgan</a> )
 ;<br/>

<b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">c<sub>1</sub></font>; <i><font color="Red">:: according to </font></i><a class="ref" href="lattices.html#D6">LATTICES:def 6</a><br/>

<b>thus </b><font color="Maroon">c<sub>2</sub></font> <a href="lattices.html#K2">"/\"</a> <font color="Maroon">c<sub>3</sub></font> = 
<font color="Maroon">c<sub>2</sub></font> <a href="robbins1.html#K4" target="_self">*'</a> <font color="Maroon">c<sub>3</sub></font>
<b>by </b><i><a class="txt" href="robbins1.html#E1:108_1_1"><i><font color="Green">E65</font></i></a>, <a class="txt" href="robbins1.html#E86"><i><font color="Green">Lemma64</font></i></a></i>
<br/>.= 
<font color="Maroon">c<sub>3</sub></font> <a href="robbins1.html#K4" target="_self">*'</a> <font color="Maroon">c<sub>2</sub></font>
<b>by </b><i><a class="txt" href="robbins1.html#E1:108_1_1"><i><font color="Green">E65</font></i></a>, <a class="ref" href="robbins1.html#T8" target="_self">Th8</a></i>
<br/>.= 
<font color="Maroon">c<sub>3</sub></font> <a href="lattices.html#K2">"/\"</a> <font color="Maroon">c<sub>2</sub></font>
<b>by </b><i><a class="txt" href="robbins1.html#E1:108_1_1"><i><font color="Green">E65</font></i></a>, <a class="txt" href="robbins1.html#E86"><i><font color="Green">Lemma64</font></i></a></i>
;<br/>


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