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







<b>assume </b><b>that </b><br/><a NAME="E1:59"/><i><font color="Green">E18</font></i>: 
<font color="Maroon">p</font> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">q</font> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a> 
 <b>and </b><br/><a NAME="E2:59"/><i><font color="Green">E20</font></i>: 
<font color="Maroon">r</font> <a href="cqc_lang.html#K12">=&gt;</a> <font color="Maroon">s</font> <a href="hidden.html#R2">in</a>  <a href="cqc_the1.html#K4">TAUT</a> 
 ;<br/>

<a NAME="E3:59"/><i><font color="Green">E24</font></i>: 
<span class="p1">(<span class="default"><font color="Maroon">p</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">r</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">r</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="procal_1.html#T20" target="_self">Th20</a></i>;<br/>
<a NAME="E4:59"/>
<span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">r</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">s</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="procal_1.html#T21" target="_self">Th21</a></i>;<br/>
<b>hence </b><a NAME="E5:59"/>
<span class="p1">(<span class="default"><font color="Maroon">p</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">r</font></span>)</span> <a href="cqc_lang.html#K12">=&gt;</a> <span class="p1">(<span class="default"><font color="Maroon">q</font> <a href="cqc_lang.html#K13">'or'</a> <font color="Maroon">s</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="lukasi_1.html#T3">LUKASI_1:3</a></i>;<br/>


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