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<b>let </b><font color="Maroon">x</font> be    <a href="finseq_1.html#M2">FinSequence</a> of  <a href="numbers.html#K1">REAL</a> , <font color="Maroon">y</font> be    <a href="finseq_1.html#M2">FinSequence</a> of  <a href="numbers.html#K1">REAL</a> ;<br/>

<b>assume </b><a NAME="E1:4"/>
 <a href="finseq_1.html#K3">len</a> <font color="Maroon">x</font> <a href="hidden.html#R1">=</a>  <a href="finseq_1.html#K3">len</a> <font color="Maroon">y</font>
 ;<br/>

<b>then reconsider </b><font color="Maroon">z</font> = <font color="Maroon">x</font>, <font color="Maroon">z2</font> = <font color="Maroon">y</font> as    <a href="finseq_2.html#M2">Element</a> of  <a href="euclid.html#K1">REAL</a> <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">x</font></span>)</span> <b>by </b><i><a class="ref" href="jordan2c.html#T52">JORDAN2C:52</a></i>;<br/>
<b>set </b><font color="Maroon">n</font> =  <a href="finseq_1.html#K3">len</a> <font color="Maroon">x</font>;<br/>
<b>reconsider </b><font color="Maroon">w</font> = <font color="Maroon">z</font>, <font color="Maroon">u</font> = <font color="Maroon">z2</font> as    <a href="finseq_2.html#M2">Element</a> of <span class="p1">(<span class="default"><a href="finseq_1.html#K3">len</a> <font color="Maroon">x</font></span>)</span> <a href="finseq_2.html#K4">-tuples_on</a> <a href="numbers.html#K1">REAL</a>  <b>by </b><i><a class="ref" href="euclid.html#D1">EUCLID:def 1</a></i>;<br/>
<a NAME="E4:4"/>
<font color="Maroon">w</font> <a href="rvsum_1.html#K8">-</a> <font color="Maroon">u</font> <a href="hidden.html#R1">=</a> <font color="Maroon">w</font> <a href="rvsum_1.html#K4">+</a> <span class="p1">(<span class="default"><a href="rvsum_1.html#K6">-</a> <font color="Maroon">u</font></span>)</span>
 
<b>by </b><i><a class="ref" href="rvsum_1.html#T52">RVSUM_1:52</a></i>;<br/>
<b>hence </b><a NAME="E5:4"/>
<font color="Maroon">x</font> <a href="rvsum_1.html#K7">-</a> <font color="Maroon">y</font> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> <a href="rvsum_1.html#K3">+</a> <span class="p1">(<span class="default"><a href="rvsum_1.html#K5">-</a> <font color="Maroon">y</font></span>)</span>
 ;<br/>


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