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<b>let </b><font color="Maroon" title="c1">BL</font> be  <a href="lattices.html#V17" title="LATTICES:attr.17">Boolean</a> <a href="lattices.html#NM1" title="LATTICES:NM.1">Lattice</a>;<br/><b>let </b><font color="Maroon" title="c2">F</font> be    <a href="lattice4.html#M3" title="LATTICE4:mode.3">Field</a> of <font color="Maroon" title="c1">BL</font>;<br/>



<a NAME="E1:46"/>
for <font color="Olive" title="b1">a</font>, <font color="Olive" title="b2">b</font> being  <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">BL</font>  st <font color="Olive" title="b1">a</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">F</font> &amp; <font color="Olive" title="b2">b</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">F</font> holds <br/>( <font color="Olive" title="b1">a</font> <a href="lattices.html#K4" title="LATTICES:func.4">"/\"</a> <font color="Olive" title="b2">b</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">F</font> &amp; <font color="Olive" title="b1">a</font> <a href="lattices.html#K3" title="LATTICES:func.3">"\/"</a> <font color="Olive" title="b2">b</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c2">F</font> )
 
<b>by </b><i><a class="ref" href="lattice4.html#D14" target="_self" title="LATTICE4:def.14">Def14</a>, <a class="ref" href="lattice4.html#T39" target="_self" title="LATTICE4:th.39">Th39</a></i>;<br/>
<b>hence </b><a NAME="E2:46"/>
<font color="Maroon" title="c2">F</font> is    <a href="lattice4.html#M2" title="LATTICE4:mode.2">ClosedSubset</a> of <font color="Maroon" title="c1">BL</font>
 <b>by </b><i><a class="ref" href="lattice4.html#D10" target="_self" title="LATTICE4:def.10">Def10</a></i>;<br/>


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