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<b>let </b><font color="Maroon">G</font> be   <a href="projpl_1.html#NM1">IncProjectivePlane</a>;<br/><b>let </b><font color="Maroon">a</font> be   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">G</font>;<br/><b>let </b><font color="Maroon">A</font> be   <a href="incsp_1.html#NM2">LINE</a> of <font color="Maroon">G</font>;<br/><b>let </b><font color="Maroon">B</font> be   <a href="incsp_1.html#NM2">LINE</a> of <font color="Maroon">G</font>;<br/>







<b>assume </b><a NAME="E1:34"/><i><font color="Green">E36</font></i>: 
<font color="Maroon">A</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> <font color="Maroon">B</font>
 ;<br/>

<a NAME="E2:34"/><b>then </b>
<font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font> <a href="projpl_1.html#R2" target="_self">on</a> <font color="Maroon">A</font>,<font color="Maroon">B</font>
 
<b>by </b><i><a class="ref" href="projpl_1.html#D1" target="_self">Def1</a></i>;<br/>
<a NAME="E3:34"/><b>then </b>
<font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font> <a href="projpl_1.html#R2" target="_self">on</a> <font color="Maroon">B</font>,<font color="Maroon">A</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E4:34"/>
( <font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font> <a href="incsp_1.html#R1">on</a> <font color="Maroon">A</font> &amp; <font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font> <a href="incsp_1.html#R1">on</a> <font color="Maroon">B</font> &amp; <font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font> <a href="hidden.html#R1">=</a> <font color="Maroon">B</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">A</font> )
 <b>by </b><i><a class="ref" href="projpl_1.html#D3" target="_self">Def3</a>, , <a class="ref" href="projpl_1.html#D1" target="_self">Def1</a></i>;<br/>

<b>assume </b><a NAME="E5:34"/>
( <font color="Maroon">a</font> <a href="incsp_1.html#R1">on</a> <font color="Maroon">A</font> &amp; <font color="Maroon">a</font> <a href="incsp_1.html#R1">on</a> <font color="Maroon">B</font> )
 ;<br/>

<a NAME="E6:34"/><b>then </b>
<font color="Maroon">a</font> <a href="projpl_1.html#R2" target="_self">on</a> <font color="Maroon">A</font>,<font color="Maroon">B</font>
 
<b>by </b><i/>;<br/>
<b>hence </b><a NAME="E7:34"/>
<font color="Maroon">a</font> <a href="hidden.html#R1">=</a> <font color="Maroon">A</font> <a href="projpl_1.html#K2" target="_self">*</a> <font color="Maroon">B</font>
 <b>by </b><i><a class="ref" href="projpl_1.html#D3" target="_self">Def3</a>, <a class="ref" href="projpl_1.html#D1" target="_self">Def1</a></i>;<br/>


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