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<b>reconsider </b><font color="Maroon">c<sub>5</sub></font> = <span class="p1"><a href="arytm_0.html#K5">[*</a><span class="default"><span class="p2">(<span class="default"><a href="arytm_0.html#K3">opp</a> <font color="Maroon">c<sub>3</sub></font></span>)</span>,<span class="p2">(<span class="default"><a href="arytm_0.html#K3">opp</a> <font color="Maroon">c<sub>4</sub></font></span>)</span></span><a href="arytm_0.html#K5">*]</a></span> as  <a href="xcmplx_0.html#V1" target="_self">complex</a>  <a href="ordinal1.html#NM1" target="_self">number</a>  <b>by </b><i><a class="ref" href="xcmplx_0.html#D2" target="_self">Def2</a></i>;<br/>
<b>take </b>
<font color="Maroon">c<sub>5</sub></font>
;<br/>

<a NAME="E2:9_1_1"/>
( 0 <a href="hidden.html#R1">=</a>  <a href="arytm_0.html#K1">+</a> <font color="Maroon">c<sub>3</sub></font>,<span class="p1">(<span class="default"><a href="arytm_0.html#K3">opp</a> <font color="Maroon">c<sub>3</sub></font></span>)</span> &amp; 0 <a href="hidden.html#R1">=</a>  <a href="arytm_0.html#K1">+</a> <font color="Maroon">c<sub>4</sub></font>,<span class="p1">(<span class="default"><a href="arytm_0.html#K3">opp</a> <font color="Maroon">c<sub>4</sub></font></span>)</span> )
 
<b>by </b><i><a class="ref" href="arytm_0.html#D4">ARYTM_0:def 4</a></i>;<br/>
<b>hence </b><a NAME="E3:9_1_1"/>
<font color="Maroon">c<sub>2</sub></font> <a href="xcmplx_0.html#K2" target="_self">+</a> <font color="Maroon">c<sub>5</sub></font> <a href="hidden.html#R1">=</a> 0
 <b>by </b><i><a class="txt" href="xcmplx_0.html#E3:9"><i><font color="Green">E7</font></i></a>, <a class="ref" href="xcmplx_0.html#D4" target="_self">Def4</a>, <a class="txt" href="xcmplx_0.html#E7"><i><font color="Green">Lemma5</font></i></a></i>;<br/>


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