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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>let </b><font color="Maroon" title="c3">h</font> be   <a href="qc_lang1.html#NM8" title="QC_LANG1:NM.8">QC-formula</a>;<br/><b>let </b><font color="Maroon" title="c4">x</font>, <font color="Maroon" title="c5">y</font> be   <a href="qc_lang1.html#NM3" title="QC_LANG1:NM.3">bound_QC-variable</a>;<br/>









<b>assume </b><b>that </b><br/><a NAME="E1:45"/><i><font color="Green" title="E35">A1</font></i>: 
( <font color="Maroon" title="c1">p</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">h</font> <a href="cqc_lang.html#K14" title="CQC_LANG:func.14">.</a> <font color="Maroon" title="c4">x</font> &amp; <font color="Maroon" title="c2">q</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">h</font> <a href="cqc_lang.html#K14" title="CQC_LANG:func.14">.</a> <font color="Maroon" title="c5">y</font> )
 <b>and </b><br/><a NAME="E2:45"/><i><font color="Green" title="E36">A2</font></i>: 
not <font color="Maroon" title="c4">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="qc_lang1.html#K23" title="QC_LANG1:func.23">still_not-bound_in</a> <font color="Maroon" title="c2">q</font>
 <b>and </b><br/><a NAME="E3:45"/><i><font color="Green" title="E37">A3</font></i>: 
not <font color="Maroon" title="c5">y</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="qc_lang1.html#K23" title="QC_LANG1:func.23">still_not-bound_in</a> <font color="Maroon" title="c3">h</font>
 ;<br/>

<a NAME="E4:45"/><i><font color="Green" title="E38">A4</font></i>: 
not <font color="Maroon" title="c4">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="qc_lang1.html#K23" title="QC_LANG1:func.23">still_not-bound_in</a> <span class="p1">(<span class="default"><a href="cqc_lang.html#K13" title="CQC_LANG:func.13">Ex</a> <font color="Maroon" title="c5">y</font>,<font color="Maroon" title="c2">q</font></span>)</span>
 
<b>by </b><i><a class="txt" href="cqc_the2.html#E2:45"><i><font color="Green" title="E36">A2</font></i></a>, <a class="ref" href="cqc_the2.html#T6" target="_self" title="CQC_THE2:th.6">Th6</a></i>;<br/>
<a NAME="E5:45"/>
<font color="Maroon" title="c1">p</font> <a href="cqc_lang.html#K9" title="CQC_LANG:func.9">=&gt;</a> <span class="p1">(<span class="default"><a href="cqc_lang.html#K13" title="CQC_LANG:func.13">Ex</a> <font color="Maroon" title="c5">y</font>,<font color="Maroon" title="c2">q</font></span>)</span> is <a href="cqc_the1.html#V2" title="CQC_THE1:attr.2">valid</a>
 
<b>by </b><i><a class="txt" href="cqc_the2.html#E1:45"><i><font color="Green" title="E35">A1</font></i></a>, <a class="txt" href="cqc_the2.html#E3:45"><i><font color="Green" title="E37">A3</font></i></a>, <a class="ref" href="cqc_the2.html#T25" target="_self" title="CQC_THE2:th.25">Th25</a></i>;<br/>
<b>hence </b><a NAME="E6:45"/>
<span class="p1">(<span class="default"><a href="cqc_lang.html#K13" title="CQC_LANG:func.13">Ex</a> <font color="Maroon" title="c4">x</font>,<font color="Maroon" title="c1">p</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#K13" title="CQC_LANG:func.13">Ex</a> <font color="Maroon" title="c5">y</font>,<font color="Maroon" title="c2">q</font></span>)</span> is <a href="cqc_the1.html#V2" title="CQC_THE1:attr.2">valid</a>
 <b>by </b><i><a class="txt" href="cqc_the2.html#E4:45"><i><font color="Green" title="E38">A4</font></i></a>, <a class="ref" href="cqc_the2.html#T22" target="_self" title="CQC_THE2:th.22">Th22</a></i>;<br/>


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