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<b>let </b><font color="Maroon">S</font> be   <a href="incsp_1.html#NM4">IncSpace</a>;<br/><b>let </b><font color="Maroon">P</font> be   <a href="incsp_1.html#NM3">PLANE</a> of <font color="Maroon">S</font>;<br/>



<b>consider </b><font color="Maroon">A</font> being   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font><b> such that </b><br/><a NAME="E2:63"/><i><font color="Green">E23</font></i>: 
<font color="Maroon">A</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#D5" target="_self">Def5</a></i>;<br/>
<b>consider </b><font color="Maroon">A1</font> being   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font>, <font color="Maroon">B1</font> being   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font>, <font color="Maroon">C1</font> being   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font>, <font color="Maroon">D1</font> being   <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font><b> such that </b><br/><a NAME="E4:63"/><i><font color="Green">E24</font></i>: 
not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a> 
 <b>by </b><i><a class="ref" href="incsp_1.html#D5" target="_self">Def5</a></i>;<br/>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="63_1"><b>now </b></a><div class="add"><b>assume </b><a NAME="E1:63_1"/><i><font color="Green">E36</font></i>: 
not <font color="Maroon">A1</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font>
 ;<br/><div><i><font color="Green">E57</font></i>: <a class="txt" onclick="hs2(this)" href="javascript:()" title="63_1_1"><b>now </b></a><div class="add"><b>assume </b><a NAME="E1:63_1_1"/><i><font color="Green">E58</font></i>: 
<font color="Maroon">A</font> <a href="incsp_1.html#R1" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 ;<br/><b>set </b><font color="Maroon">Q</font> =  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>;<br/><a NAME="E2:63_1_1"/><i><font color="Green">E60</font></i>: 
<font color="Maroon">A1</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> <font color="Maroon">B1</font>
 <b>by </b><i>, <a class="ref" href="incsp_1.html#T11" target="_self">Th11</a></i>;<br/><a NAME="E3:63_1_1"/><b>then </b><i><font color="Green">E61</font></i>: 
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#T17" target="_self">Th17</a></i>;<br/><a NAME="E4:63_1_1"/><b>then </b>
<font color="Maroon">A1</font> <a href="incsp_1.html#R1" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 <b>by </b><i/>;<br/><a NAME="E5:63_1_1"/><b>then </b><i><font color="Green">E62</font></i>: 
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 <b>by </b><i>, </i>;<br/><a NAME="E6:63_1_1"/><i><font color="Green">E63</font></i>: 
not <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#NR6" target="_self">is_collinear</a> 
 <b>by </b><i>, <a class="txt" href="incsp_1.html#E2:63"><i><font color="Green">E23</font></i></a></i>;<br/><a NAME="E7:63_1_1"/><b>then </b><i><font color="Green">E64</font></i>: 
<span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#T18" target="_self">Th18</a></i>;<br/><a NAME="E8:63_1_1"/><b>then </b>
( <font color="Maroon">D1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> implies <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="subset_1.html#K4">\/</a> <span class="p1"><a href="domain_1.html#K6">{</a><span class="default"><font color="Maroon">D1</font></span><a href="domain_1.html#K6">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> )
 <b>by </b><i><a class="ref" href="incsp_1.html#D2" target="_self">Def2</a></i>;<br/><a NAME="E9:63_1_1"/><b>then </b><i><font color="Green">E65</font></i>: 
( <font color="Maroon">D1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> implies <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> )
 <b>by </b><i><a class="ref" href="enumset1.html#T46">ENUMSET1:46</a></i>;<br/><a NAME="E10:63_1_1"/>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 <b>by </b><i>, <a class="ref" href="incsp_1.html#T17" target="_self">Th17</a></i>;<br/><a NAME="E11:63_1_1"/><b>then </b>
( <font color="Maroon">C1</font> <a href="incsp_1.html#R1" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font> implies <span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="subset_1.html#K4">\/</a> <span class="p1"><a href="domain_1.html#K6">{</a><span class="default"><font color="Maroon">C1</font></span><a href="domain_1.html#K6">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font> )
 <b>by </b><i><a class="ref" href="incsp_1.html#D1" target="_self">Def1</a></i>;<br/><a NAME="E12:63_1_1"/><b>then </b>
( <font color="Maroon">C1</font> <a href="incsp_1.html#R1" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font> implies <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font> )
 <b>by </b><i><a class="ref" href="enumset1.html#T43">ENUMSET1:43</a></i>;<br/><a NAME="E13:63_1_1"/><b>then </b><i><font color="Green">E66</font></i>: 
not <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#NR6" target="_self">is_collinear</a> 
 <b>by </b><i>, , , , , <a class="txt" href="incsp_1.html#E4:63"><i><font color="Green">E24</font></i></a></i>;<br/><a NAME="E14:63_1_1"/>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="subset_1.html#K4">\/</a> <span class="p1"><a href="domain_1.html#K6">{</a><span class="default"><font color="Maroon">C1</font></span><a href="domain_1.html#K6">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>
 <b>by </b><i>, <a class="ref" href="enumset1.html#T43">ENUMSET1:43</a></i>;<br/><a NAME="E15:63_1_1"/><b>then </b>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#D4" target="_self">Def4</a></i>;<br/><a NAME="E16:63_1_1"/><b>then </b>
(  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font> <a href="incsp_1.html#R3" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> &amp; <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> )
 <b>by </b><i>, , , <a class="ref" href="incsp_1.html#D5" target="_self">Def5</a>, <a class="ref" href="incsp_1.html#T18" target="_self">Th18</a></i>;<br/><a NAME="E17:63_1_1"/><b>then </b>
( <font color="Maroon">A</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> &amp; <font color="Maroon">A1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> &amp; <font color="Maroon">C1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font> )
 <b>by </b><i>, <a class="ref" href="incsp_1.html#D5" target="_self">Def5</a>, </i>;<br/><a NAME="E18:63_1_1"/><b>then </b>
<span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>
 <b>by </b><i/>;<br/><a NAME="E19:63_1_1"/><b>then </b>
not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font>,<font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a> 
 <b>by </b><i>, , , , <a class="ref" href="incsp_1.html#T12" target="_self">Th12</a></i>;<br/><b>hence </b><a NAME="E20:63_1_1"/>
 ex <font color="Olive">A</font>, <font color="Olive">B</font>, <font color="Olive">C</font>, <font color="Olive">D</font> being  <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font> st <br/>( <font color="Olive">A</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font> &amp; not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Olive">A</font>,<font color="Olive">B</font>,<font color="Olive">C</font>,<font color="Olive">D</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i/>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hs2(this)" href="javascript:()" title="63_1_2"><b>now </b></a><div class="add"><b>assume </b><a NAME="E1:63_1_2"/><i><font color="Green">E67</font></i>: 
not <font color="Maroon">A</font> <a href="incsp_1.html#R1" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 ;<br/><b>set </b><font color="Maroon">Q</font> =  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>;<br/><a NAME="E2:63_1_2"/><i><font color="Green">E68</font></i>: 
<font color="Maroon">A1</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> <font color="Maroon">B1</font>
 <b>by </b><i>, <a class="ref" href="incsp_1.html#T11" target="_self">Th11</a></i>;<br/><a NAME="E3:63_1_2"/><b>then </b>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R4" target="_self">on</a>  <a href="incsp_1.html#K1" target="_self">Line</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#T17" target="_self">Th17</a></i>;<br/><a NAME="E4:63_1_2"/><b>then </b><i><font color="Green">E69</font></i>: 
not <span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#NR6" target="_self">is_collinear</a> 
 <b>by </b><i>, , <a class="txt" href="incsp_1.html#E4:63"><i><font color="Green">E24</font></i></a></i>;<br/><a NAME="E5:63_1_2"/><b>then </b><i><font color="Green">E70</font></i>: 
<span class="p1"><a href="domain_1.html#K8">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font></span><a href="domain_1.html#K8">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#T18" target="_self">Th18</a></i>;<br/><a NAME="E6:63_1_2"/><b>then </b>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="subset_1.html#K4">\/</a> <span class="p1"><a href="domain_1.html#K6">{</a><span class="default"><font color="Maroon">A</font></span><a href="domain_1.html#K6">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>
 <b>by </b><i><a class="ref" href="enumset1.html#T43">ENUMSET1:43</a></i>;<br/><a NAME="E7:63_1_2"/><b>then </b>
<span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>
 <b>by </b><i><a class="ref" href="incsp_1.html#D2" target="_self">Def2</a></i>;<br/><a NAME="E8:63_1_2"/><b>then </b>
( <span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> implies <span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font></span><a href="domain_1.html#K7">}</a></span> <a href="subset_1.html#K4">\/</a> <span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> )
 <b>by </b><i><a class="ref" href="incsp_1.html#D4" target="_self">Def4</a></i>;<br/><a NAME="E9:63_1_2"/><b>then </b>
( <span class="p1"><a href="domain_1.html#K7">{</a><span class="default"><font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K7">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> implies <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#R5" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> )
 <b>by </b><i><a class="ref" href="enumset1.html#T45">ENUMSET1:45</a></i>;<br/><a NAME="E10:63_1_2"/><b>then </b>
(  not <font color="Maroon">C1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> or  not <font color="Maroon">D1</font> <a href="incsp_1.html#R2" target="_self">on</a>  <a href="incsp_1.html#K2" target="_self">Plane</a> <font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font> )
 <b>by </b><i>, , </i>;<br/><a NAME="E11:63_1_2"/><b>then </b>
(  not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  or  not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">A</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i>, , <a class="ref" href="incsp_1.html#T12" target="_self">Th12</a></i>;<br/><a NAME="E12:63_1_2"/><b>then </b>
(  not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">C1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  or  not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Maroon">A</font>,<font color="Maroon">A1</font>,<font color="Maroon">B1</font>,<font color="Maroon">D1</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i><a class="ref" href="enumset1.html#T110">ENUMSET1:110</a></i>;<br/><b>hence </b><a NAME="E13:63_1_2"/>
 ex <font color="Olive">A</font>, <font color="Olive">B</font>, <font color="Olive">C</font>, <font color="Olive">D</font> being  <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font> st <br/>( <font color="Olive">A</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font> &amp; not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Olive">A</font>,<font color="Olive">B</font>,<font color="Olive">C</font>,<font color="Olive">D</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i/>;<br/></div><b>end;</b></div><b>hence </b><a NAME="E4:63_1"/>
 ex <font color="Olive">A</font>, <font color="Olive">B</font>, <font color="Olive">C</font>, <font color="Olive">D</font> being  <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font> st <br/>( <font color="Olive">A</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font> &amp; not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Olive">A</font>,<font color="Olive">B</font>,<font color="Olive">C</font>,<font color="Olive">D</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i/>;<br/></div><b>end;</b></div>
<b>hence </b><a NAME="E6:63"/>
 ex <font color="Olive">A</font>, <font color="Olive">B</font>, <font color="Olive">C</font>, <font color="Olive">D</font> being  <a href="incsp_1.html#NM1">POINT</a> of <font color="Maroon">S</font> st <br/>( <font color="Olive">A</font> <a href="incsp_1.html#R2" target="_self">on</a> <font color="Maroon">P</font> &amp; not <span class="p1"><a href="domain_1.html#K9">{</a><span class="default"><font color="Olive">A</font>,<font color="Olive">B</font>,<font color="Olive">C</font>,<font color="Olive">D</font></span><a href="domain_1.html#K9">}</a></span> <a href="incsp_1.html#NR7" target="_self">is_coplanar</a>  )
 <b>by </b><i/>;<br/>


</div>
