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<b>let </b><font color="Maroon">L</font> be   <a href="waybel_0.html#NM8">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>thus </b><a NAME="E1:19"/>
( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="lattice7.html#K3" target="_self">Join-IRR</a> <font color="Maroon">L</font> implies ( <font color="Maroon">x</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="yellow_0.html#K3">Bottom</a> <font color="Maroon">L</font> &amp; ( for <font color="Olive">b</font>, <font color="Olive">c</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>  holds <br/>(  not <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> <a href="lattice3.html#K13">"\/"</a> <font color="Olive">c</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">c</font> ) ) ) )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="19_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:19_1"/>
<font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="lattice7.html#K3" target="_self">Join-IRR</a> <font color="Maroon">L</font>
 ;<br/>

<a NAME="E2:19_1"/><b>then </b>
 ex <font color="Olive">a</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font> st <br/>( <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">a</font> &amp; <font color="Olive">a</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="yellow_0.html#K3">Bottom</a> <font color="Maroon">L</font> &amp; ( for <font color="Olive">b</font>, <font color="Olive">c</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>  holds <br/>(  not <font color="Olive">a</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> <a href="lattice3.html#K13">"\/"</a> <font color="Olive">c</font> or <font color="Olive">a</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> or <font color="Olive">a</font> <a href="hidden.html#R1">=</a> <font color="Olive">c</font> ) ) )
 
;<br/>
<b>hence </b><a NAME="E3:19_1"/>
( <font color="Maroon">x</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="yellow_0.html#K3">Bottom</a> <font color="Maroon">L</font> &amp; ( for <font color="Olive">b</font>, <font color="Olive">c</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>  holds <br/>(  not <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> <a href="lattice3.html#K13">"\/"</a> <font color="Olive">c</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">c</font> ) ) )
 ;<br/>


</div><b>end;</b></div>

<b>thus </b><a NAME="E2:19"/>
( <font color="Maroon">x</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="yellow_0.html#K3">Bottom</a> <font color="Maroon">L</font> &amp; ( for <font color="Olive">b</font>, <font color="Olive">c</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">L</font>  holds <br/>(  not <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> <a href="lattice3.html#K13">"\/"</a> <font color="Olive">c</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">b</font> or <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Olive">c</font> ) ) implies <font color="Maroon">x</font> <a href="hidden.html#R2">in</a>  <a href="lattice7.html#K3" target="_self">Join-IRR</a> <font color="Maroon">L</font> )
 ;<br/>


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