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<b>let </b><font color="Maroon">AFP</font> be   <a href="diraf.html#NM2">AffinPlane</a>;<br/><b>let </b><font color="Maroon">a</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font>;<br/><b>let </b><font color="Maroon">b</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font>;<br/><b>let </b><font color="Maroon">K</font> be   <a href="struct_0.html#NM2">Subset</a> of <font color="Maroon">AFP</font>;<br/>







<b>assume </b><a NAME="E1:26"/><i><font color="Green">E43</font></i>: 
( <font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="aff_1.html#R2">//</a> <font color="Maroon">K</font> &amp; not <font color="Maroon">a</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> )
 ;<br/>

<b>let </b><font color="Maroon">y</font> be   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font>;<br/>

<a NAME="E2:26"/><i><font color="Green">E44</font></i>: 
( <font color="Maroon">b</font>,<font color="Maroon">a</font> <a href="aff_1.html#R2">//</a> <font color="Maroon">K</font> &amp; not <font color="Maroon">b</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> )
 
<b>by </b><i>, <a class="ref" href="aff_1.html#T48">AFF_1:48</a>, <a class="ref" href="aff_1.html#T49">AFF_1:49</a></i>;<br/>
<b>then consider </b><font color="Maroon">x</font> being   <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font><b> such that </b><br/><a NAME="E4:26"/><i><font color="Green">E45</font></i>: 
( ( <font color="Maroon">y</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Maroon">y</font> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> ) or ( not <font color="Maroon">y</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp;  ex <font color="Olive">p</font>, <font color="Olive">p'</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font> st <br/>( <font color="Olive">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p'</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p</font>,<font color="Maroon">b</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Maroon">y</font> &amp; <font color="Olive">p</font>,<font color="Maroon">a</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Maroon">x</font> &amp; <font color="Maroon">y</font>,<font color="Maroon">x</font> <a href="aff_1.html#R2">//</a> <font color="Maroon">K</font> ) ) )
 <b>by </b><i/>;<br/>
<a NAME="E5:26"/>
( ( <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Maroon">x</font> <a href="hidden.html#R1">=</a> <font color="Maroon">y</font> ) or ( not <font color="Maroon">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp;  ex <font color="Olive">p</font>, <font color="Olive">p'</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font> st <br/>( <font color="Olive">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p'</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p</font>,<font color="Maroon">a</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Maroon">x</font> &amp; <font color="Olive">p</font>,<font color="Maroon">b</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Maroon">y</font> &amp; <font color="Maroon">x</font>,<font color="Maroon">y</font> <a href="aff_1.html#R2">//</a> <font color="Maroon">K</font> ) ) )
 
<b>by </b><i>, , </i>;<br/>
<b>hence </b><a NAME="E6:26"/>
 ex <font color="Olive">x</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font> st <br/>( ( <font color="Olive">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">x</font> <a href="hidden.html#R1">=</a> <font color="Maroon">y</font> ) or ( not <font color="Olive">x</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp;  ex <font color="Olive">p</font>, <font color="Olive">p'</font> being  <a href="struct_0.html#NM1">Element</a> of <font color="Maroon">AFP</font> st <br/>( <font color="Olive">p</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p'</font> <a href="hidden.html#R2">in</a> <font color="Maroon">K</font> &amp; <font color="Olive">p</font>,<font color="Maroon">a</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Olive">x</font> &amp; <font color="Olive">p</font>,<font color="Maroon">b</font> <a href="analoaf.html#R2">//</a> <font color="Olive">p'</font>,<font color="Maroon">y</font> &amp; <font color="Olive">x</font>,<font color="Maroon">y</font> <a href="aff_1.html#R2">//</a> <font color="Maroon">K</font> ) ) )
 ;<br/>


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