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<b>let </b><font color="Maroon">L</font> be   <a href="lattices.html#NM1">Lattice</a>;<br/><b>let </b><font color="Maroon">p</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">q</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">F</font> be    <a href="filter_0.html#M1" target="_self">Filter</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">p'</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="filter_0.html#K8" target="_self">latt</a> <font color="Maroon">F</font></span>)</span>, <font color="Maroon">q'</font> be   <a href="struct_0.html#NM1">Element</a> of <span class="p1">(<span class="default"><a href="filter_0.html#K8" target="_self">latt</a> <font color="Maroon">F</font></span>)</span>;<br/>









<b>assume </b><a NAME="E1:69"/><i><font color="Green">E28</font></i>: 
( <font color="Maroon">p</font> <a href="hidden.html#R1">=</a> <font color="Maroon">p'</font> &amp; <font color="Maroon">q</font> <a href="hidden.html#R1">=</a> <font color="Maroon">q'</font> )
 ;<br/>

<b>consider </b><font color="Maroon">o1</font> being   <a href="binop_1.html#NM2">BinOp</a> of <font color="Maroon">F</font>, <font color="Maroon">o2</font> being   <a href="binop_1.html#NM2">BinOp</a> of <font color="Maroon">F</font><b> such that </b><br/><a NAME="E3:69"/><i><font color="Green">E42</font></i>: 
( <font color="Maroon">o1</font> <a href="hidden.html#R1">=</a> the <a href="lattices.html#U2">L_join</a> of <font color="Maroon">L</font> <a href="realset1.html#K1">||</a> <font color="Maroon">F</font> &amp; <font color="Maroon">o2</font> <a href="hidden.html#R1">=</a> the <a href="lattices.html#U1">L_meet</a> of <font color="Maroon">L</font> <a href="realset1.html#K1">||</a> <font color="Maroon">F</font> &amp;  <a href="filter_0.html#K8" target="_self">latt</a> <font color="Maroon">F</font> <a href="hidden.html#R1">=</a>  <a href="lattices.html#G3">LattStr</a>(# <font color="Maroon">F</font>,<font color="Maroon">o1</font>,<font color="Maroon">o2</font> #) )
 <b>by </b><i/>;<br/>
<a NAME="E4:69"/>
( <font color="Maroon">p'</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font> &amp; <font color="Maroon">q'</font> <a href="hidden.html#R2">in</a> <font color="Maroon">F</font> &amp;  <a href="relset_1.html#K4">dom</a> <font color="Maroon">o1</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="mcart_1.html#K12">[:</a><span class="default"><font color="Maroon">F</font>,<font color="Maroon">F</font></span><a href="mcart_1.html#K12">:]</a></span> &amp;  <a href="relset_1.html#K4">dom</a> <font color="Maroon">o2</font> <a href="hidden.html#R1">=</a> <span class="p1"><a href="mcart_1.html#K12">[:</a><span class="default"><font color="Maroon">F</font>,<font color="Maroon">F</font></span><a href="mcart_1.html#K12">:]</a></span> )
 
<b>by </b><i>, <a class="ref" href="funct_2.html#D1">FUNCT_2:def 1</a></i>;<br/>
<a NAME="E5:69"/><b>then </b><i><font color="Green">E43</font></i>: 
( <span class="p1"><a href="domain_1.html#K1">[</a><span class="default"><font color="Maroon">p</font>,<font color="Maroon">q</font></span><a href="domain_1.html#K1">]</a></span> <a href="hidden.html#R2">in</a>  <a href="relset_1.html#K4">dom</a> <font color="Maroon">o1</font> &amp; <span class="p1"><a href="domain_1.html#K1">[</a><span class="default"><font color="Maroon">p</font>,<font color="Maroon">q</font></span><a href="domain_1.html#K1">]</a></span> <a href="hidden.html#R2">in</a>  <a href="relset_1.html#K4">dom</a> <font color="Maroon">o2</font> )
 
<b>by </b><i><a class="ref" href="filter_0.html#T12" target="_self">Th12</a>, <a class="ref" href="zfmisc_1.html#T106">ZFMISC_1:106</a></i>;<br/>
<b>thus </b><a NAME="E6:69"/>
<font color="Maroon">p</font> <a href="lattices.html#K3">"\/"</a> <font color="Maroon">q</font> <a href="hidden.html#R1">=</a> <font color="Maroon">p'</font> <a href="lattices.html#K3">"\/"</a> <font color="Maroon">q'</font>
 <b>by </b><i><a class="ref" href="filter_0.html#T12" target="_self">Th12</a>, , <a class="ref" href="filter_0.html#T15" target="_self">Th15</a>, <a class="ref" href="funct_1.html#T70">FUNCT_1:70</a></i>;<br/>

<b>thus </b><a NAME="E7:69"/>
<font color="Maroon">p</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">q</font> <a href="hidden.html#R1">=</a> <font color="Maroon">p'</font> <a href="lattices.html#K4">"/\"</a> <font color="Maroon">q'</font>
 <b>by </b><i><a class="ref" href="filter_0.html#T12" target="_self">Th12</a>, , <a class="ref" href="filter_0.html#T15" target="_self">Th15</a>, <a class="ref" href="funct_1.html#T70">FUNCT_1:70</a></i>;<br/>


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