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<b>let </b><font color="Maroon">I</font> be   <a href="filter_0.html#NM2">I_Lattice</a>;<br/><b>let </b><font color="Maroon">FI</font> be    <a href="filter_0.html#M1">Filter</a> of <font color="Maroon">I</font>;<br/><b>let </b><font color="Maroon">i</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">I</font>;<br/><b>let </b><font color="Maroon">j</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">I</font>;<br/><b>let </b><font color="Maroon">k</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">I</font>;<br/>









<a NAME="E1:79"/><i><font color="Green">E68</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">j</font></span>)</span> <a href="lattices.html#K4">"/\"</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">k</font></span>)</span> <a href="lattices.html#R3">[=</a> <font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">j</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">k</font></span>)</span>
 
<b>by </b><i/>;<br/>
<b>assume </b><a NAME="E2:79"/>
( <font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">j</font> <a href="hidden.html#R2">in</a> <font color="Maroon">FI</font> &amp; <font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">k</font> <a href="hidden.html#R2">in</a> <font color="Maroon">FI</font> )
 ;<br/>

<a NAME="E3:79"/><b>then </b>
<span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">j</font></span>)</span> <a href="lattices.html#K4">"/\"</a> <span class="p1">(<span class="default"><font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <font color="Maroon">k</font></span>)</span> <a href="hidden.html#R2">in</a> <font color="Maroon">FI</font>
 
<b>by </b><i><a class="ref" href="filter_0.html#D1">FILTER_0:def 1</a></i>;<br/>
<b>hence </b><a NAME="E4:79"/>
<font color="Maroon">i</font> <a href="filter_0.html#K4">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">j</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">k</font></span>)</span> <a href="hidden.html#R2">in</a> <font color="Maroon">FI</font>
 <b>by </b><i>, <a class="ref" href="filter_0.html#T9">FILTER_0:9</a></i>;<br/>


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