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<b>let </b><font color="Maroon" title="c1">B</font> be   <a href="lattices.html#NM8" title="LATTICES:NM.8">B_Lattice</a>;<br/><b>let </b><font color="Maroon" title="c2">IB</font> be    <a href="filter_2.html#M2" title="FILTER_2:mode.2">Ideal</a> of <font color="Maroon" title="c1">B</font>;<br/>



<b>reconsider </b><font color="Maroon" title="c3">FB</font> = <font color="Maroon" title="c2">IB</font> <a href="filter_2.html#K15" title="FILTER_2:func.15">.:</a>  as    <a href="filter_2.html#M1" title="FILTER_2:mode.1">Filter</a> of <font color="Maroon" title="c1">B</font> <a href="lattice2.html#K1" title="LATTICE2:func.1">.:</a>  ;<br/>
<b>assume </b><a NAME="E2:84"/>
<font color="Maroon" title="c2">IB</font> <a href="filter_2.html#R2" title="FILTER_2:pred.2">is_max-ideal</a> 
 ;<br/>

<a NAME="E3:84"/><b>then </b><i><font color="Green" title="E31">A1</font></i>: 
<font color="Maroon" title="c3">FB</font> <a href="filter_0.html#NR1" title="FILTER_0:NR.1">is_ultrafilter</a> 
 
<b>by </b><i><a class="ref" href="filter_2.html#T33" target="_self" title="FILTER_2:th.33">Th33</a></i>;<br/>
<b>let </b><font color="Maroon" title="c4">a</font> be   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">B</font>;<br/>

<a NAME="E4:84"/>
( <font color="Maroon" title="c4">a</font> <a href="filter_2.html#K5" title="FILTER_2:func.5">.:</a>  <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c4">a</font> &amp; <span class="p1">(<span class="default"><font color="Maroon" title="c4">a</font> <a href="filter_2.html#K5" title="FILTER_2:func.5">.:</a> </span>)</span> <a href="lattices.html#K7" title="LATTICES:func.7">`</a>  <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c4">a</font> <a href="lattices.html#K7" title="LATTICES:func.7">`</a>  )
 
<b>by </b><i><a class="txt" href="filter_2.html#E70"><i><font color="Green" title="E29">Lm3</font></i></a></i>;<br/>
<b>hence </b><a NAME="E5:84"/>
( <font color="Maroon" title="c4">a</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">IB</font> iff not <font color="Maroon" title="c4">a</font> <a href="lattices.html#K7" title="LATTICES:func.7">`</a>  <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">IB</font> )
 <b>by </b><i><a class="txt" href="filter_2.html#E3:84"><i><font color="Green" title="E31">A1</font></i></a>, <a class="ref" href="filter_0.html#T59" title="FILTER_0:th.59">FILTER_0:59</a></i>;<br/>


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