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<b>let </b><font color="Maroon">M</font> be   <a href="midsp_1.html#NM1">MidSp</a>;<br/><b>let </b><font color="Maroon">W</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="midsp_1.html#K13" target="_self">setvect</a> <font color="Maroon">M</font>;<br/><b>let </b><font color="Maroon">W1</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="midsp_1.html#K13" target="_self">setvect</a> <font color="Maroon">M</font>;<br/><b>let </b><font color="Maroon">W2</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="midsp_1.html#K13" target="_self">setvect</a> <font color="Maroon">M</font>;<br/>







<b>assume </b><b>that </b><br/><a NAME="E1:68"/><i><font color="Green">E37</font></i>: 
<font color="Maroon">W</font> <a href="midsp_1.html#K14" target="_self">+</a> <font color="Maroon">W1</font> <a href="hidden.html#R1">=</a>  <a href="midsp_1.html#K9" target="_self">ID</a> <font color="Maroon">M</font>
 <b>and </b><br/><a NAME="E2:68"/><i><font color="Green">E38</font></i>: 
<font color="Maroon">W</font> <a href="midsp_1.html#K14" target="_self">+</a> <font color="Maroon">W2</font> <a href="hidden.html#R1">=</a>  <a href="midsp_1.html#K9" target="_self">ID</a> <font color="Maroon">M</font>
 ;<br/>

<b>reconsider </b><font color="Maroon">x</font> = <font color="Maroon">W</font>, <font color="Maroon">y1</font> = <font color="Maroon">W1</font>, <font color="Maroon">y2</font> = <font color="Maroon">W2</font> as    <a href="midsp_1.html#M1" target="_self">Vector</a> of <font color="Maroon">M</font> <b>by </b><i><a class="ref" href="midsp_1.html#T24" target="_self">Th24</a></i>;<br/>
<font color="Maroon">x</font> <a href="midsp_1.html#K10" target="_self">+</a> <font color="Maroon">y1</font> = 
<font color="Maroon">W</font> <a href="midsp_1.html#K14" target="_self">+</a> <font color="Maroon">W2</font>
<b>by </b><i>, , <a class="ref" href="midsp_1.html#T25" target="_self">Th25</a></i>
<br/>.= 
<font color="Maroon">x</font> <a href="midsp_1.html#K10" target="_self">+</a> <font color="Maroon">y2</font>
<b>by </b><i><a class="ref" href="midsp_1.html#T25" target="_self">Th25</a></i>
;<br/>
<b>hence </b><a NAME="E5:68"/>
<font color="Maroon">W1</font> <a href="hidden.html#R1">=</a> <font color="Maroon">W2</font>
 <b>by </b><i><a class="ref" href="midsp_1.html#T23" target="_self">Th23</a></i>;<br/>


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