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<b>let </b><font color="Maroon">L</font> be   <a href="lattices.html#NM2">D_Lattice</a>;<br/><b>let </b><font color="Maroon">a</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/>





<a NAME="E1:28"/>
( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="openlatt.html#K10" target="_self">SF_have</a> <font color="Maroon">a</font> iff  ex <font color="Olive">F</font> being   <a href="filter_0.html#M1">Filter</a> of <font color="Maroon">L</font> st <br/>( <font color="Olive">F</font> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> &amp; <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Olive">F</font> ) )
 
;<br/>
<b>hence </b><a NAME="E2:28"/>
( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="openlatt.html#K10" target="_self">SF_have</a> <font color="Maroon">a</font> iff ( <font color="Maroon">x</font> is    <a href="filter_0.html#M1">Filter</a> of <font color="Maroon">L</font> &amp; <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">x</font> ) )
 ;<br/>


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