<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon" title="c1">IPP</font> be  <a href="incproj.html#V6" title="INCPROJ:attr.6">2-dimensional</a> <a href="incproj.html#V10" title="INCPROJ:attr.10">Desarguesian</a> <a href="incproj.html#NM2" title="INCPROJ:NM.2">IncProjSp</a>;<br/><b>let </b><font color="Maroon" title="c2">A</font> be   <a href="incsp_1.html#NM2" title="INCSP_1:NM.2">LINE</a> of <font color="Maroon" title="c1">IPP</font>;<br/>



<b>consider </b><font color="Maroon" title="c3">o</font> being   <a href="incsp_1.html#NM1" title="INCSP_1:NM.1">POINT</a> of <font color="Maroon" title="c1">IPP</font><b> such that </b><br/><a NAME="E2:13"/><i><font color="Green" title="E10">A1</font></i>: 
not <font color="Maroon" title="c3">o</font> <a href="incsp_1.html#R1" title="INCSP_1:pred.1">on</a> <font color="Maroon" title="c2">A</font>
 <b>by </b><i><a class="ref" href="projred1.html#T1" title="PROJRED1:th.1">PROJRED1:1</a></i>;<br/>
<a NAME="E3:13"/>
 <a href="relat_1.html#K6" title="RELAT_1:func.6">id</a> <span class="p1">(<span class="default"><a href="projred2.html#K1" title="PROJRED2:func.1">CHAIN</a> <font color="Maroon" title="c2">A</font></span>)</span> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="projred1.html#K1" title="PROJRED1:func.1">IncProj</a> <font color="Maroon" title="c2">A</font>,<font color="Maroon" title="c3">o</font>,<font color="Maroon" title="c2">A</font>
 
<b>by </b><i><a class="txt" href="projred2.html#E2:13"><i><font color="Green" title="E10">A1</font></i></a>, <a class="ref" href="projred2.html#T11" target="_self" title="PROJRED2:th.11">Th11</a></i>;<br/>
<b>hence </b><a NAME="E4:13"/>
 <a href="relat_1.html#K6" title="RELAT_1:func.6">id</a> <span class="p1">(<span class="default"><a href="projred2.html#K1" title="PROJRED2:func.1">CHAIN</a> <font color="Maroon" title="c2">A</font></span>)</span> is    <a href="projred2.html#M1" title="PROJRED2:mode.1">Projection</a> of <font color="Maroon" title="c1">IPP</font>
 <b>by </b><i><a class="txt" href="projred2.html#E2:13"><i><font color="Green" title="E10">A1</font></i></a>, <a class="ref" href="projred2.html#D3" target="_self" title="PROJRED2:def.3">Def3</a></i>;<br/>


</div>
