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<b>let </b><font color="Maroon">S</font> be  non <a href="xboole_0.html#V1">empty</a>  <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">R</font> be  <a href="partfun1.html#V1">total</a>  <a href="relset_1.html#M2">Relation</a> of <font color="Maroon">S</font>,<font color="Maroon">S</font>;<br/><b>let </b><font color="Maroon">s</font> be    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font>;<br/><b>let </b><font color="Maroon">BASSIGN</font> be  non <a href="xboole_0.html#V1">empty</a> <a href="subset_1.html#NM2">Subset</a> of <span class="p1">(<span class="default"><a href="modelc_1.html#K32" target="_self">ModelSP</a> <font color="Maroon">S</font></span>)</span>;<br/><b>let </b><font color="Maroon">f</font> be   <a href="modelc_1.html#NM2">Assign</a> of <span class="p1">(<span class="default"><a href="modelc_1.html#K50" target="_self">CTLModel</a> <font color="Maroon">R</font>,<font color="Maroon">BASSIGN</font></span>)</span>;<br/>









<a NAME="E1:143"/><i><font color="Green">E27</font></i>: 
( <font color="Maroon">s</font> <a href="modelc_1.html#R3" target="_self">|=</a>  <a href="modelc_1.html#K27" target="_self">EX</a> <font color="Maroon">f</font> implies  ex <font color="Olive">s1</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font> st <br/>( <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">s</font>,<font color="Olive">s1</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font> &amp; <font color="Olive">s1</font> <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font> ) )
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="143_1"><b>proof </b></a><div class="add">

<b>assume </b><a NAME="E1:143_1"/>
<font color="Maroon">s</font> <a href="modelc_1.html#R3" target="_self">|=</a>  <a href="modelc_1.html#K27" target="_self">EX</a> <font color="Maroon">f</font>
 ;<br/>

<b>then consider </b><font color="Maroon">pai</font> being    <a href="modelc_1.html#M1" target="_self">inf_path</a> of <font color="Maroon">R</font><b> such that </b><br/><a NAME="E3:143_1"/><i><font color="Green">E28</font></i>: 
<font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 0 <a href="hidden.html#R1">=</a> <font color="Maroon">s</font>
 <b>and </b><br/><a NAME="E4:143_1"/><i><font color="Green">E50</font></i>: 
<font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 1 <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font>
 <b>by </b><i/>;<br/>
<b>set </b><font color="Maroon">s1</font> = <font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 1;<br/>
<a NAME="E5:143_1"/>
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><span class="p2">(<span class="default"><font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 0</span>)</span>,<span class="p2">(<span class="default"><font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> <span class="p3">(<span class="default">0 <a href="binop_2.html#K23">+</a> 1</span>)</span></span>)</span></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E6:143_1"/>
 ex <font color="Olive">s1</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font> st <br/>( <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">s</font>,<font color="Olive">s1</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font> &amp; <font color="Olive">s1</font> <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font> )
 <b>by </b><i>, </i>;<br/>


</div><b>end;</b></div>
<a NAME="E2:143"/>
(  ex <font color="Olive">s1</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font> st <br/>( <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">s</font>,<font color="Olive">s1</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font> &amp; <font color="Olive">s1</font> <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font> ) implies <font color="Maroon">s</font> <a href="modelc_1.html#R3" target="_self">|=</a>  <a href="modelc_1.html#K27" target="_self">EX</a> <font color="Maroon">f</font> )
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="143_2"><b>proof </b></a><div class="add">

<b>given </b><font color="Maroon">s1</font> being    <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font><b> such that </b><a NAME="E1:143_2"/><i><font color="Green">E52</font></i>: 
<span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">s</font>,<font color="Maroon">s1</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font>
 <b>and </b><br/><a NAME="E2:143_2"/><i><font color="Green">E53</font></i>: 
<font color="Maroon">s1</font> <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font>
 ;<br/>

<b>consider </b><font color="Maroon">pai</font> being    <a href="modelc_1.html#M1" target="_self">inf_path</a> of <font color="Maroon">R</font><b> such that </b><br/><a NAME="E4:143_2"/><i><font color="Green">E54</font></i>: 
<font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 0 <a href="hidden.html#R1">=</a> <font color="Maroon">s</font>
 <b>and </b><br/><a NAME="E5:143_2"/><i><font color="Green">E55</font></i>: 
<font color="Maroon">pai</font> <a href="funct_2.html#K3">.</a> 1 <a href="hidden.html#R1">=</a> <font color="Maroon">s1</font>
 <b>by </b><i>, </i>;<br/>
<b>thus </b><a NAME="E6:143_2"/>
<font color="Maroon">s</font> <a href="modelc_1.html#R3" target="_self">|=</a>  <a href="modelc_1.html#K27" target="_self">EX</a> <font color="Maroon">f</font>
 <b>by </b><i>, , , </i>;<br/>


</div><b>end;</b></div>
<b>hence </b><a NAME="E3:143"/>
( <font color="Maroon">s</font> <a href="modelc_1.html#R3" target="_self">|=</a>  <a href="modelc_1.html#K27" target="_self">EX</a> <font color="Maroon">f</font> iff  ex <font color="Olive">s1</font> being   <a href="subset_1.html#M1">Element</a> of <font color="Maroon">S</font> st <br/>( <span class="p1"><a href="tarski.html#K4">[</a><span class="default"><font color="Maroon">s</font>,<font color="Olive">s1</font></span><a href="tarski.html#K4">]</a></span> <a href="hidden.html#R2">in</a> <font color="Maroon">R</font> &amp; <font color="Olive">s1</font> <a href="modelc_1.html#R3" target="_self">|=</a> <font color="Maroon">f</font> ) )
 <b>by </b><i/>;<br/>


</div>
