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<b>let </b><font color="Maroon">x1</font> be    <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a> , <font color="Maroon">x2</font> be    <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a> ;<br/>

<a NAME="E1:12"/><i><font color="Green">E30</font></i>: 
 <a href="turing_1.html#K4" target="_self">Prefix</a> <span class="p1"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>,1 <a href="hidden.html#R1">=</a> <span class="p1"><a href="finseq_1.html#K12">&lt;*</a><span class="default"><font color="Maroon">x1</font></span><a href="finseq_1.html#K12">*&gt;</a></span>
 
<b>by </b><i><a class="ref" href="finseq_6.html#T5">FINSEQ_6:5</a></i>;<br/>
<b>reconsider </b><font color="Maroon">y1</font> = <font color="Maroon">x1</font> as    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K4">INT</a>  <b>by </b><i><a class="ref" href="int_1.html#D2">INT_1:def 2</a></i>;<br/>
<b>thus </b> <a href="gr_cy_1.html#K2">Sum</a> <span class="p1">(<span class="default"><a href="turing_1.html#K4" target="_self">Prefix</a> <span class="p2"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>,1</span>)</span> = 
 <a href="gr_cy_1.html#K2">Sum</a> <span class="p1"><a href="finseq_1.html#K12">&lt;*</a><span class="default"><font color="Maroon">y1</font></span><a href="finseq_1.html#K12">*&gt;</a></span>
<b>by </b><i/>
<br/>.= 
<font color="Maroon">x1</font>
<b>by </b><i><a class="ref" href="gr_cy_1.html#T21">GR_CY_1:21</a></i>
;<br/>

<a NAME="E4:12"/><i><font color="Green">E31</font></i>: 
 <a href="finseq_1.html#K3">len</a> <span class="p1"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span> <a href="hidden.html#R1">=</a> 2
 
<b>by </b><i><a class="ref" href="finseq_1.html#T61">FINSEQ_1:61</a></i>;<br/>
<a NAME="E5:12"/><i><font color="Green">E32</font></i>: 
 <a href="turing_1.html#K4" target="_self">Prefix</a> <span class="p1"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>,2 <a href="hidden.html#R1">=</a> <span class="p1"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>
 
<b>by </b><i>, <a class="ref" href="finseq_3.html#T55">FINSEQ_3:55</a></i>;<br/>
<b>reconsider </b><font color="Maroon">y2</font> = <font color="Maroon">x2</font> as    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K4">INT</a>  <b>by </b><i><a class="ref" href="int_1.html#D2">INT_1:def 2</a></i>;<br/>
<b>thus </b> <a href="gr_cy_1.html#K2">Sum</a> <span class="p1">(<span class="default"><a href="turing_1.html#K4" target="_self">Prefix</a> <span class="p2"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">x1</font>,<font color="Maroon">x2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>,2</span>)</span> = 
 <a href="gr_cy_1.html#K2">Sum</a> <span class="p1"><a href="finseq_4.html#K2">&lt;*</a><span class="default"><font color="Maroon">y1</font>,<font color="Maroon">y2</font></span><a href="finseq_4.html#K2">*&gt;</a></span>
<b>by </b><i/>
<br/>.= 
<font color="Maroon">x1</font> <a href="nat_1.html#K1">+</a> <font color="Maroon">x2</font>
<b>by </b><i/>
;<br/>


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