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<b>let </b><font color="Maroon">L</font> be   <a href="lattices.html#NM8">B_Lattice</a>;<br/><b>let </b><font color="Maroon">X</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">Y</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">Z</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/><b>let </b><font color="Maroon">V</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>;<br/>









<b>assume </b><b>that </b><br/><a NAME="E1:29"/><i><font color="Green">E12</font></i>: 
<font color="Maroon">X</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">Y</font>
 <b>and </b><br/><a NAME="E2:29"/><i><font color="Green">E13</font></i>: 
<font color="Maroon">Z</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">V</font>
 ;<br/>

<a NAME="E3:29"/><i><font color="Green">E14</font></i>: 
<font color="Maroon">X</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">V</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">Y</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">V</font>
 
<b>by </b><i><a class="txt" href="boolealg.html#E5"><i><font color="Green">Lemma11</font></i></a>, <a class="ref" href="lattices.html#T27">LATTICES:27</a></i>;<br/>
<a NAME="E4:29"/>
<font color="Maroon">Y</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">V</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">Y</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">Z</font>
 
<b>by </b><i><a class="txt" href="boolealg.html#E1:29"><i><font color="Green">E12</font></i></a>, <a class="ref" href="boolealg.html#D4" target="_self">Def4</a></i>;<br/>
<b>hence </b><a NAME="E5:29"/>
<font color="Maroon">X</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">V</font> <a href="lattices.html#R3">[=</a> <font color="Maroon">Y</font> <a href="boolealg.html#K1" target="_self">\</a> <font color="Maroon">Z</font>
 <b>by </b><i><a class="txt" href="boolealg.html#E2:29"><i><font color="Green">E13</font></i></a>, <a class="ref" href="lattices.html#T25">LATTICES:25</a></i>;<br/>


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