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<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="midsp_1.html#NM1">MidSp</a>;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font>, <font color="Maroon">c<sub>4</sub></font> be    <a href="subset_1.html#M1">Element</a> of  <a href="midsp_1.html#K14" target="_self">setvect</a> <font color="Maroon">c<sub>1</sub></font>;<br/>







<b>assume </b><b>that </b><br/><a NAME="E1:69"/><i><font color="Green">E51</font></i>: 
<font color="Maroon">c<sub>2</sub></font> <a href="midsp_1.html#K15" target="_self">+</a> <font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a>  <a href="midsp_1.html#K10" target="_self">ID</a> <font color="Maroon">c<sub>1</sub></font>
 <b>and </b><br/><a NAME="E2:69"/><i><font color="Green">E52</font></i>: 
<font color="Maroon">c<sub>2</sub></font> <a href="midsp_1.html#K15" target="_self">+</a> <font color="Maroon">c<sub>4</sub></font> <a href="hidden.html#R1">=</a>  <a href="midsp_1.html#K10" target="_self">ID</a> <font color="Maroon">c<sub>1</sub></font>
 ;<br/>

<b>reconsider </b><font color="Maroon">c<sub>5</sub></font> = <font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>6</sub></font> = <font color="Maroon">c<sub>3</sub></font>, <font color="Maroon">c<sub>7</sub></font> = <font color="Maroon">c<sub>4</sub></font> as    <a href="midsp_1.html#M1" target="_self">Vector</a> of <font color="Maroon">c<sub>1</sub></font> <b>by </b><i><a class="ref" href="midsp_1.html#T71" target="_self">Th71</a></i>;<br/>
<font color="Maroon">c<sub>5</sub></font> <a href="midsp_1.html#K11" target="_self">+</a> <font color="Maroon">c<sub>6</sub></font> = 
<font color="Maroon">c<sub>2</sub></font> <a href="midsp_1.html#K15" target="_self">+</a> <font color="Maroon">c<sub>4</sub></font>
<b>by </b><i><a class="txt" href="midsp_1.html#E1:69"><i><font color="Green">E51</font></i></a>, <a class="txt" href="midsp_1.html#E2:69"><i><font color="Green">E52</font></i></a>, <a class="ref" href="midsp_1.html#D14" target="_self">Def14</a></i>
<br/>.= 
<font color="Maroon">c<sub>5</sub></font> <a href="midsp_1.html#K11" target="_self">+</a> <font color="Maroon">c<sub>7</sub></font>
<b>by </b><i><a class="ref" href="midsp_1.html#D14" target="_self">Def14</a></i>
;<br/>
<b>hence </b><a NAME="E5:69"/>
<font color="Maroon">c<sub>3</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>4</sub></font>
 <b>by </b><i><a class="ref" href="midsp_1.html#T67" target="_self">Th67</a></i>;<br/>


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