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<b>let </b><font color="Maroon">u</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>thus </b><a NAME="E1:34_2_1"/>
( <font color="Maroon">v</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  &amp; <font color="Maroon">w</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  implies ( <font color="Maroon">u</font> <a href="hidden.html#R1">=</a> <font color="Maroon">v</font> <a href="xboolean.html#K4">'&amp;'</a> <font color="Maroon">w</font> iff <font color="Maroon">u</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  ) )
 ;<br/>

<b>assume </b><a NAME="E2:34_2_1"/>
( <font color="Maroon">v</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  or <font color="Maroon">w</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  )
 ;<br/>

<a NAME="E3:34_2_1"/><b>then </b>
( <font color="Maroon">v</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  or <font color="Maroon">w</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  )
 
<b>by </b><i><a class="ref" href="xboolean.html#D3">XBOOLEAN:def 3</a></i>;<br/>
<b>hence </b><a NAME="E4:34_2_1"/>
( <font color="Maroon">u</font> <a href="hidden.html#R1">=</a> <font color="Maroon">v</font> <a href="xboolean.html#K4">'&amp;'</a> <font color="Maroon">w</font> iff <font color="Maroon">u</font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  )
 ;<br/>


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