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<b>let </b><font color="Maroon">p</font> be    <a href="subset_1.html#M2">Element</a> of  <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/><b>let </b><font color="Maroon">q</font> be    <a href="subset_1.html#M2">Element</a> of  <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/><b>let </b><font color="Maroon">r</font> be    <a href="subset_1.html#M2">Element</a> of  <a href="cqc_lang.html#K7">CQC-WFF</a> ;<br/>





<b>assume </b><a NAME="E1:2"/>
<font color="Maroon">p</font> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">r</font></span>)</span> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a> 
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="cqc_the1.html#D11">CQC_THE1:def 11</a><br/>

<a NAME="E2:2"/><b>then </b>
<font color="Maroon">p</font> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">r</font></span>)</span> is <a href="cqc_the1.html#V2">valid</a>
 
<b>by </b><i><a class="ref" href="cqc_the1.html#D11">CQC_THE1:def 11</a></i>;<br/>
<a NAME="E3:2"/><b>then </b>
<span class="p1">(<span class="default"><font color="Maroon">p</font> <a href="cqc_lang.html#K11">'&amp;'</a> <font color="Maroon">q</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">r</font> is <a href="cqc_the1.html#V2">valid</a>
 
<b>by </b><i/>;<br/>
<a NAME="E4:2"/><b>then </b>
( <span class="p1">(<span class="default"><font color="Maroon">p</font> <a href="cqc_lang.html#K11">'&amp;'</a> <font color="Maroon">q</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">r</font> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a>  &amp; <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K11">'&amp;'</a> <font color="Maroon">p</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">p</font> <a href="cqc_lang.html#K11">'&amp;'</a> <font color="Maroon">q</font></span>)</span> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a>  )
 
<b>by </b><i><a class="ref" href="cqc_the1.html#T81">CQC_THE1:81</a>, <a class="ref" href="cqc_the1.html#D11">CQC_THE1:def 11</a></i>;<br/>
<b>hence </b><a NAME="E5:2"/>
<span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K11">'&amp;'</a> <font color="Maroon">p</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">r</font> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a> 
 <b>by </b><i><a class="ref" href="lukasi_1.html#T3">LUKASI_1:3</a></i>; <i><font color="Red">:: according to </font></i><a class="ref" href="cqc_the1.html#D11">CQC_THE1:def 11</a><br/>


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