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<a NAME="E1:39_1_1"/><i><font color="Green">E18</font></i>: 
<span class="p1"><a href="domain_1.html#K1">[</a><span class="default"><span class="p2">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span>,<span class="p2">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K19" target="_self">`2</a> </span>)</span></span><a href="domain_1.html#K1">]</a></span> is    <a href="subset_1.html#M1">Element</a> of  <a href="substut1.html#K16" target="_self">QC-Sub-WFF</a> 
 
<b>by </b><i><a class="ref" href="substut1.html#T10" target="_self">Th10</a></i>;<br/>
<a NAME="E2:39_1_1"/><i><font color="Green">E19</font></i>: 
<font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a>  <a href="hidden.html#R1">=</a>  <a href="qc_lang1.html#K10">@</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="qc_lang1.html#D12">QC_LANG1:def 12</a></i>;<br/>
<a NAME="E3:39_1_1"/><i><font color="Green">E20</font></i>: 
<span class="p1"><a href="domain_1.html#K1">[</a><span class="default"><span class="p2">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span>,<span class="p2">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K19" target="_self">`2</a> </span>)</span></span><a href="domain_1.html#K1">]</a></span> is    <a href="subset_1.html#M1">Element</a> of  <a href="substut1.html#K16" target="_self">QC-Sub-WFF</a> 
 
<b>by </b><i><a class="ref" href="substut1.html#T10" target="_self">Th10</a></i>;<br/>
<a NAME="E4:39_1_1"/><i><font color="Green">E21</font></i>: 
<font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a>  <a href="hidden.html#R1">=</a>  <a href="qc_lang1.html#K10">@</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span>
 
<b>by </b><i><a class="ref" href="qc_lang1.html#D12">QC_LANG1:def 12</a></i>;<br/>
<a NAME="E5:39_1_1"/>
<span class="p1">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span> <a href="qc_lang1.html#K13">'&amp;'</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span> <a href="hidden.html#R1">=</a> <span class="p1">(<span class="default"><span class="p2"><a href="finseq_1.html#K12">&lt;*</a><span class="default"><span class="p3"><a href="domain_1.html#K1">[</a><span class="default">2,0</span><a href="domain_1.html#K1">]</a></span></span><a href="finseq_1.html#K12">*&gt;</a></span> <a href="finseq_1.html#K8">^</a> <span class="p2">(<span class="default"><a href="qc_lang1.html#K10">@</a> <span class="p3">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span></span>)</span></span>)</span> <a href="finseq_1.html#K8">^</a> <span class="p1">(<span class="default"><a href="qc_lang1.html#K10">@</a> <span class="p2">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span></span>)</span>
 
<b>by </b><i><a class="ref" href="qc_lang1.html#D15">QC_LANG1:def 15</a></i>;<br/>
<b>hence </b><a NAME="E6:39_1_1"/>
<span class="p1"><a href="domain_1.html#K1">[</a><span class="default"><span class="p2">(<span class="default"><span class="p3">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span> <a href="qc_lang1.html#K13">'&amp;'</a> <span class="p3">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="substut1.html#K18" target="_self">`1</a> </span>)</span></span>)</span>,<span class="p2">(<span class="default"><font color="Maroon">c<sub>1</sub></font> <a href="substut1.html#K19" target="_self">`2</a> </span>)</span></span><a href="domain_1.html#K1">]</a></span> is    <a href="subset_1.html#M1">Element</a> of  <a href="substut1.html#K16" target="_self">QC-Sub-WFF</a> 
 <b>by </b><i><a class="txt" href="substut1.html#E1:39"><i><font color="Green">E17</font></i></a>, <a class="txt" href="substut1.html#E1:39_1_1"><i><font color="Green">E18</font></i></a>, <a class="txt" href="substut1.html#E2:39_1_1"><i><font color="Green">E19</font></i></a>, <a class="txt" href="substut1.html#E3:39_1_1"><i><font color="Green">E20</font></i></a>, <a class="txt" href="substut1.html#E4:39_1_1"><i><font color="Green">E21</font></i></a>, <a class="ref" href="substut1.html#D16" target="_self">Def16</a></i>;<br/>


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