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<b>let </b><font color="Maroon" title="c1">F</font> be    <a href="subset_1.html#M1" title="SUBSET_1:mode.1">Element</a> of  <a href="qc_lang1.html#K8" title="QC_LANG1:func.8">QC-WFF</a> ;<br/><b>let </b><font color="Maroon" title="c2">G2</font>, <font color="Maroon" title="c3">G1</font> be    <a href="qc_lang4.html#M1" title="QC_LANG4:mode.1">Subformula</a> of <font color="Maroon" title="c1">F</font>;<br/><b>let </b><font color="Maroon" title="c4">t1</font> be    <a href="qc_lang4.html#M2" title="QC_LANG4:mode.2">Entry_Point_in_Subformula_Tree</a> of <font color="Maroon" title="c3">G1</font>;<br/><b>let </b><font color="Maroon" title="c5">s</font> be   <a href="finseq_1.html#NM1" title="FINSEQ_1:NM.1">FinSequence</a>;<br/>









<b>assume </b><a NAME="E1:71"/><i><font color="Green" title="E60">A1</font></i>: 
<font color="Maroon" title="c4">t1</font> <a href="finseq_1.html#K7" title="FINSEQ_1:func.7">^</a> <font color="Maroon" title="c5">s</font> is    <a href="qc_lang4.html#M2" title="QC_LANG4:mode.2">Entry_Point_in_Subformula_Tree</a> of <font color="Maroon" title="c2">G2</font>
 ;<br/>

<a NAME="E2:71"/>
<span class="p1">(<span class="default"><a href="qc_lang4.html#K2" title="QC_LANG4:func.2">tree_of_subformulae</a> <font color="Maroon" title="c1">F</font></span>)</span> <a href="trees_2.html#K3" title="TREES_2:func.3">.</a> <font color="Maroon" title="c4">t1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">G1</font>
 
<b>by </b><i><a class="ref" href="qc_lang4.html#D5" target="_self" title="QC_LANG4:def.5">Def5</a></i>;<br/>
<a NAME="E3:71"/><b>then </b><i><font color="Green" title="E61">A2</font></i>: 
<font color="Maroon" title="c4">t1</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">F</font> <a href="qc_lang4.html#K3" title="QC_LANG4:func.3">-entry_points_in_subformula_tree_of</a> <font color="Maroon" title="c3">G1</font>
 
<b>by </b><i><a class="ref" href="qc_lang4.html#D3" target="_self" title="QC_LANG4:def.3">Def3</a></i>;<br/>
<b>consider </b><font color="Maroon" title="c6">t'</font> being   <a href="finseq_1.html#NM1" title="FINSEQ_1:NM.1">FinSequence</a><b> such that </b><br/><a NAME="E5:71"/><i><font color="Green" title="E62">A3</font></i>: 
<font color="Maroon" title="c6">t'</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c4">t1</font> <a href="finseq_1.html#K7" title="FINSEQ_1:func.7">^</a> <font color="Maroon" title="c5">s</font>
 ;<br/>
<a NAME="E6:71"/>
<font color="Maroon" title="c6">t'</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <span class="p1">{<span class="default"> <font color="Olive" title="b1">t2</font> where <font color="Olive" title="b1">t2</font> is    <a href="qc_lang4.html#M2" title="QC_LANG4:mode.2">Entry_Point_in_Subformula_Tree</a> of <font color="Maroon" title="c2">G2</font> : <font color="Olive" title="b1">t2</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Olive" title="b1">t2</font> </span>}</span> 
 
<b>by </b><i><a class="txt" href="qc_lang4.html#E1:71"><i><font color="Green" title="E60">A1</font></i></a>, <a class="txt" href="qc_lang4.html#E5:71"><i><font color="Green" title="E62">A3</font></i></a></i>;<br/>
<a NAME="E7:71"/><b>then </b>
<font color="Maroon" title="c6">t'</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="qc_lang4.html#K4" title="QC_LANG4:func.4">entry_points_in_subformula_tree</a> <font color="Maroon" title="c2">G2</font>
 
<b>by </b><i><a class="ref" href="qc_lang4.html#T68" target="_self" title="QC_LANG4:th.68">Th68</a></i>;<br/>
<b>hence </b><a NAME="E8:71"/>
<font color="Maroon" title="c5">s</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c3">G1</font> <a href="qc_lang4.html#K3" title="QC_LANG4:func.3">-entry_points_in_subformula_tree_of</a> <font color="Maroon" title="c2">G2</font>
 <b>by </b><i><a class="txt" href="qc_lang4.html#E3:71"><i><font color="Green" title="E61">A2</font></i></a>, <a class="txt" href="qc_lang4.html#E5:71"><i><font color="Green" title="E62">A3</font></i></a>, <a class="ref" href="qc_lang4.html#T58" target="_self" title="QC_LANG4:th.58">Th58</a></i>;<br/>


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