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<b>let </b><font color="Maroon" title="c1">p</font>, <font color="Maroon" title="c2">q</font> be    <a href="subset_1.html#M2" title="SUBSET_1:mode.2">Element</a> of  <a href="cqc_lang.html#K4" title="CQC_LANG:func.4">CQC-WFF</a> ;<br/>



<b>assume </b><b>that </b><br/><a NAME="E1:49"/><i><font color="Green" title="E42">A1</font></i>: 
<font color="Maroon" title="c1">p</font> is <a href="qc_lang1.html#V6" title="QC_LANG1:attr.6">closed</a>
 <b>and </b><br/><a NAME="E2:49"/><i><font color="Green" title="E43">A2</font></i>: 
<font color="Maroon" title="c1">p</font> <a href="cqc_the3.html#R1" title="CQC_THE3:pred.1">|-</a> <font color="Maroon" title="c2">q</font>
 ;<br/>

<a NAME="E3:49"/>
 <a href="cqc_the1.html#NR5" title="CQC_THE1:NR.5">|-</a> <font color="Maroon" title="c1">p</font> <a href="cqc_lang.html#K9" title="CQC_LANG:func.9">=&gt;</a> <font color="Maroon" title="c2">q</font>
 
<b>by </b><i><a class="txt" href="cqc_the3.html#E1:49"><i><font color="Green" title="E42">A1</font></i></a>, <a class="txt" href="cqc_the3.html#E2:49"><i><font color="Green" title="E43">A2</font></i></a>, <a class="ref" href="cqc_the3.html#T41" target="_self" title="CQC_THE3:th.41">Th41</a></i>;<br/>
<a NAME="E4:49"/><b>then </b>
 <a href="cqc_the1.html#NR5" title="CQC_THE1:NR.5">|-</a> <span class="p1">(<span class="default"><a href="cqc_lang.html#K7" title="CQC_LANG:func.7">'not'</a> <font color="Maroon" title="c2">q</font></span>)</span> <a href="cqc_lang.html#K9" title="CQC_LANG:func.9">=&gt;</a> <span class="p1">(<span class="default"><a href="cqc_lang.html#K7" title="CQC_LANG:func.7">'not'</a> <font color="Maroon" title="c1">p</font></span>)</span>
 
<b>by </b><i><a class="ref" href="lukasi_1.html#T63" title="LUKASI_1:th.63">LUKASI_1:63</a></i>;<br/>
<b>hence </b><a NAME="E5:49"/>
 <a href="cqc_lang.html#K7" title="CQC_LANG:func.7">'not'</a> <font color="Maroon" title="c2">q</font> <a href="cqc_the3.html#R1" title="CQC_THE3:pred.1">|-</a>  <a href="cqc_lang.html#K7" title="CQC_LANG:func.7">'not'</a> <font color="Maroon" title="c1">p</font>
 <b>by </b><i><a class="ref" href="cqc_the3.html#T39" target="_self" title="CQC_THE3:th.39">Th39</a></i>;<br/>


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