<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon">c<sub>1</sub></font> be  <a href="margrel1.html#V2" target="_self">boolean</a>  <a href="hidden.html#M1">set</a> ;<br/>

<b>thus </b><a NAME="E1:38"/>
( <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  implies  <a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  )
 <b>by </b><i><a class="ref" href="margrel1.html#D16" target="_self">Def16</a></i>;<br/>

<b>thus </b><a NAME="E2:38"/>
(  <a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  implies <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  )
 <b>by </b><i><a class="ref" href="margrel1.html#D16" target="_self">Def16</a></i>;<br/>

<b>thus </b><a NAME="E3:38"/>
( <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  implies  <a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  )
 <b>by </b><i><a class="ref" href="margrel1.html#D16" target="_self">Def16</a></i>;<br/>

<b>thus </b><a NAME="E4:38"/>
(  <a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a>  implies <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a>  )
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="38_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:38_1"/>
 <a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K7" target="_self">FALSE</a> 
 ;<br/>

<a NAME="E2:38_1"/><b>then </b>
 <a href="margrel1.html#K9" target="_self">'not'</a> <span class="p1">(<span class="default"><a href="margrel1.html#K9" target="_self">'not'</a> <font color="Maroon">c<sub>1</sub></font></span>)</span> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a> 
 
<b>by </b><i><a class="ref" href="margrel1.html#D16" target="_self">Def16</a></i>;<br/>
<b>hence </b><a NAME="E3:38_1"/>
<font color="Maroon">c<sub>1</sub></font> <a href="hidden.html#R1">=</a>  <a href="margrel1.html#K8" target="_self">TRUE</a> 
 ;<br/>


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


</div>
