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<b>let </b><font color="Maroon">a</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K1">REAL</a> ;<br/><b>let </b><font color="Maroon">b</font> be    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K1">REAL</a> ;<br/>



<b>reconsider </b><font color="Maroon">a'</font> = <font color="Maroon">a</font>, <font color="Maroon">b'</font> = <font color="Maroon">b</font> as    <a href="subset_1.html#M1">Element</a> of  <a href="numbers.html#K1">REAL</a>  ;<br/>
<b>thus </b><a NAME="E2:8"/>
 <a href="complex1.html#K3" target="_self">Re</a> <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <div><a class="txt" onclick="hs2(this)" href="javascript:()" title="8_1"><b>proof </b></a><div class="add">

<div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_1_1"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:8_1_1"/>
( <font color="Maroon">b</font> <a href="hidden.html#R1">=</a> 0 or <font color="Maroon">b</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0 )
 </span>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_1_1_1"><b>suppose </b></a><a NAME="E1:8_1_1_1"/>
<font color="Maroon">b</font> <a href="hidden.html#R1">=</a> 0
 ;<br/><div class="add"><a NAME="E2:8_1_1_1"/><b>then </b>
<span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i><a class="ref" href="arytm_0.html#D7">ARYTM_0:def 7</a></i>;<br/><b>hence </b><a NAME="E3:8_1_1_1"/>
 <a href="complex1.html#K3" target="_self">Re</a> <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i/>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_1_1_2"><b>suppose </b></a><a NAME="E1:8_1_1_2"/>
<font color="Maroon">b</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0
 ;<br/><div class="add"><a NAME="E2:8_1_1_2"/><b>then </b><i><font color="Green">E21</font></i>: 
<span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> 0,1 <a href="funct_4.html#K5">--&gt;</a> <font color="Maroon">a'</font>,<font color="Maroon">b'</font>
 <b>by </b><i><a class="ref" href="arytm_0.html#D7">ARYTM_0:def 7</a></i>;<br/><b>then reconsider </b><font color="Maroon">f</font> = <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> as   <a href="funct_2.html#NM1">Function</a> of 2, <a href="numbers.html#K1">REAL</a>  <b>by </b><i/>;<br/><a NAME="E4:8_1_1_2"/><i><font color="Green">E22</font></i>: 
not <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R2">in</a>  <a href="numbers.html#K1">REAL</a> 
 <b>by </b><i>, <a class="ref" href="arytm_0.html#T10">ARYTM_0:10</a></i>;<br/><a NAME="E5:8_1_1_2"/>
<font color="Maroon">f</font> <a href="funct_1.html#K1">.</a> 0 <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i>, <a class="ref" href="funct_4.html#T66">FUNCT_4:66</a></i>;<br/><b>hence </b><a NAME="E6:8_1_1_2"/>
 <a href="complex1.html#K3" target="_self">Re</a> <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div></div><b>end;</b></div>

</div><b>end;</b></div>

<div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_2"><b>per </b></a><a class="txt" onclick="hs(this)" href="javascript:()"><b>cases </b></a><span class="hide"><a NAME="E1:8_2"/>
( <font color="Maroon">b</font> <a href="hidden.html#R1">=</a> 0 or <font color="Maroon">b</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0 )
 </span>;<br/><div class="add"><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_2_1"><b>suppose </b></a><a NAME="E1:8_2_1"/><i><font color="Green">E30</font></i>: 
<font color="Maroon">b</font> <a href="hidden.html#R1">=</a> 0
 ;<br/><div class="add"><a NAME="E2:8_2_1"/><b>then </b>
<span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>
 <b>by </b><i><a class="ref" href="arytm_0.html#D7">ARYTM_0:def 7</a></i>;<br/><b>hence </b><a NAME="E3:8_2_1"/>
 <a href="complex1.html#K4" target="_self">Im</a> <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">b</font>
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div><div><a class="txt" onclick="hsNdiv(this)" href="javascript:()" title="8_2_2"><b>suppose </b></a><a NAME="E1:8_2_2"/>
<font color="Maroon">b</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0
 ;<br/><div class="add"><a NAME="E2:8_2_2"/><b>then </b><i><font color="Green">E35</font></i>: 
<span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> 0,1 <a href="funct_4.html#K5">--&gt;</a> <font color="Maroon">a'</font>,<font color="Maroon">b'</font>
 <b>by </b><i><a class="ref" href="arytm_0.html#D7">ARYTM_0:def 7</a></i>;<br/><b>then reconsider </b><font color="Maroon">f</font> = <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> as   <a href="funct_2.html#NM1">Function</a> of 2, <a href="numbers.html#K1">REAL</a>  <b>by </b><i/>;<br/><a NAME="E4:8_2_2"/><i><font color="Green">E36</font></i>: 
not <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R2">in</a>  <a href="numbers.html#K1">REAL</a> 
 <b>by </b><i>, <a class="ref" href="arytm_0.html#T10">ARYTM_0:10</a></i>;<br/><a NAME="E5:8_2_2"/>
<font color="Maroon">f</font> <a href="funct_1.html#K1">.</a> 1 <a href="hidden.html#R1">=</a> <font color="Maroon">b</font>
 <b>by </b><i>, <a class="ref" href="funct_4.html#T66">FUNCT_4:66</a></i>;<br/><b>hence </b><a NAME="E6:8_2_2"/>
 <a href="complex1.html#K4" target="_self">Im</a> <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font></span><a href="arytm_0.html#K5">*]</a></span> <a href="hidden.html#R1">=</a> <font color="Maroon">b</font>
 <b>by </b><i>, </i>;<br/></div><b>end;</b></div></div><b>end;</b></div>

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