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<b>defpred </b><font color="Maroon">S<sub>1</sub></font>[   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a> ] <b>means </b><font color="Maroon">k</font> <a href="newton.html#K2">|^</a> <font color="Maroon">a<sub>1</sub></font> is   <a href="int_1.html#NM1">Integer</a>;<br/>
<a NAME="E1:9_1_1"/><i><font color="Green">E40</font></i>: 
<font color="Maroon">S<sub>1</sub></font>[0]
 
<b>by </b><i><a class="ref" href="newton.html#T9">NEWTON:9</a></i>;<br/>
<a NAME="E2:9_1_1"/><i><font color="Green">E41</font></i>: 
for <font color="Olive">a</font> being   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a>   st <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">a</font>] holds <br/><font color="Maroon">S<sub>1</sub></font>[<font color="Olive">a</font> <a href="nat_1.html#K1">+</a> 1]
 
<div><a class="txt" onclick="hs2(this)" href="javascript:()" title="9_1_1_1"><b>proof </b></a><div class="add">

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

<b>assume </b><a NAME="E1:9_1_1_1"/>
<font color="Maroon">k</font> <a href="newton.html#K2">|^</a> <font color="Maroon">a</font> is   <a href="int_1.html#NM1">Integer</a>
 ;<br/>

<b>then reconsider </b><font color="Maroon">b</font> = <font color="Maroon">k</font> <a href="newton.html#K2">|^</a> <font color="Maroon">a</font> as   <a href="int_1.html#NM1">Integer</a> ;<br/>
<a NAME="E3:9_1_1_1"/>
<font color="Maroon">k</font> <a href="newton.html#K2">|^</a> <span class="p1">(<span class="default"><font color="Maroon">a</font> <a href="nat_1.html#K1">+</a> 1</span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">k</font> <a href="xcmplx_0.html#K3">*</a> <font color="Maroon">b</font>
 
<b>by </b><i><a class="ref" href="newton.html#T11">NEWTON:11</a></i>;<br/>
<b>hence </b><a NAME="E4:9_1_1_1"/>
<font color="Maroon">S<sub>1</sub></font>[<font color="Maroon">a</font> <a href="nat_1.html#K1">+</a> 1]
 ;<br/>


</div><b>end;</b></div>
<a NAME="E3:9_1_1"/>
for <font color="Olive">a</font> being   <a href="subset_1.html#M2">Element</a> of  <a href="numbers.html#K5">NAT</a>  holds  <font color="Maroon">S<sub>1</sub></font>[<font color="Olive">a</font>]
 
<b>from </b><i><a class="ref" href="nat_1.html#S1">NAT_1:sch 1</a>(, );<br/></i>
<b>hence </b><a NAME="E4:9_1_1"/>
<font color="Maroon">k</font> <a href="newton.html#K2">|^</a> <font color="Maroon">a</font> is <a href="int_1.html#V1">integer</a>
 ;<br/>


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