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<b>let </b><font color="Maroon" title="c1">V</font> be  non <a href="struct_0.html#V7" title="STRUCT_0:attr.7">trivial</a> <a href="rlvect_1.html#NM2" title="RLVECT_1:NM.2">RealLinearSpace</a>;<br/><b>let </b><font color="Maroon" title="c2">p</font>, <font color="Maroon" title="c3">q</font> be   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">V</font>;<br/>





<b>assume </b><a NAME="E1:43"/><i><font color="Green" title="E32">A1</font></i>: 
( <font color="Maroon" title="c2">p</font> <a href="anproj_1.html#NR1" title="ANPROJ_1:NR.1">is_Prop_Vect</a>  &amp; <font color="Maroon" title="c3">q</font> <a href="anproj_1.html#NR1" title="ANPROJ_1:NR.1">is_Prop_Vect</a>  )
 ;<br/>

<a NAME="E2:43"/><b>then </b><i><font color="Green" title="E33">A2</font></i>: 
<font color="Maroon" title="c2">p</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="anproj_1.html#K1" title="ANPROJ_1:func.1">Proper_Vectors_of</a> <font color="Maroon" title="c1">V</font>
 
<b>by </b><i><a class="ref" href="anproj_1.html#T26" target="_self" title="ANPROJ_1:th.26">Th26</a></i>;<br/>
<div><i><font color="Green" title="E34">A3</font></i>: <a class="txt" onclick="hs2(this)" href="javascript:()" title="43_1"><b>now </b></a><div class="add"><b>assume </b><a NAME="E1:43_1"/>
 <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c2">p</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c3">q</font>
 ;<br/><a NAME="E2:43_1"/><b>then </b>
<span class="p1"><a href="tarski.html#K4" title="TARSKI:func.4">[</a><span class="default"><font color="Maroon" title="c2">p</font>,<font color="Maroon" title="c3">q</font></span><a href="tarski.html#K4" title="TARSKI:func.4">]</a></span> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="anproj_1.html#K2" title="ANPROJ_1:func.2">Proportionality_as_EqRel_of</a> <font color="Maroon" title="c1">V</font>
 <b>by </b><i><a class="txt" href="anproj_1.html#E2:43"><i><font color="Green" title="E33">A2</font></i></a>, <a class="ref" href="eqrel_1.html#T44" title="EQREL_1:th.44">EQREL_1:44</a></i>;<br/><b>hence </b><a NAME="E3:43_1"/>
 <a href="anproj_1.html#R1" title="ANPROJ_1:pred.1">are_Prop</a> <font color="Maroon" title="c2">p</font>,<font color="Maroon" title="c3">q</font>
 <b>by </b><i><a class="ref" href="anproj_1.html#T29" target="_self" title="ANPROJ_1:th.29">Th29</a></i>;<br/></div><b>end;</b></div>
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="43_2"><b>now </b></a><div class="add"><b>assume </b><a NAME="E1:43_2"/>
 <a href="anproj_1.html#R1" title="ANPROJ_1:pred.1">are_Prop</a> <font color="Maroon" title="c2">p</font>,<font color="Maroon" title="c3">q</font>
 ;<br/><a NAME="E2:43_2"/><b>then </b>
<span class="p1"><a href="tarski.html#K4" title="TARSKI:func.4">[</a><span class="default"><font color="Maroon" title="c2">p</font>,<font color="Maroon" title="c3">q</font></span><a href="tarski.html#K4" title="TARSKI:func.4">]</a></span> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a>  <a href="anproj_1.html#K2" title="ANPROJ_1:func.2">Proportionality_as_EqRel_of</a> <font color="Maroon" title="c1">V</font>
 <b>by </b><i><a class="txt" href="anproj_1.html#E1:43"><i><font color="Green" title="E32">A1</font></i></a>, <a class="ref" href="anproj_1.html#T29" target="_self" title="ANPROJ_1:th.29">Th29</a></i>;<br/><b>hence </b><a NAME="E3:43_2"/>
 <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c2">p</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c3">q</font>
 <b>by </b><i><a class="txt" href="anproj_1.html#E2:43"><i><font color="Green" title="E33">A2</font></i></a>, <a class="ref" href="eqrel_1.html#T44" title="EQREL_1:th.44">EQREL_1:44</a></i>;<br/></div><b>end;</b></div>
<b>hence </b><a NAME="E5:43"/>
(  <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c2">p</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="anproj_1.html#K3" title="ANPROJ_1:func.3">Dir</a> <font color="Maroon" title="c3">q</font> iff  <a href="anproj_1.html#R1" title="ANPROJ_1:pred.1">are_Prop</a> <font color="Maroon" title="c2">p</font>,<font color="Maroon" title="c3">q</font> )
 <b>by </b><i><a class="txt" href="anproj_1.html#E3:43"><i><font color="Green" title="E34">A3</font></i></a></i>;<br/>


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