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



<b>assume </b><a NAME="E1:25"/><i><font color="Green">E13</font></i>: 
<font color="Maroon">y</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> 0
 ;<br/>

<b>thus </b> <a href="arytm_0.html#K2" target="_self">*</a> <span class="p1">(<span class="default"><a href="arytm_0.html#K2" target="_self">*</a> <font color="Maroon">x</font>,<font color="Maroon">y</font></span>)</span>,<span class="p1">(<span class="default"><a href="arytm_0.html#K4" target="_self">inv</a> <font color="Maroon">y</font></span>)</span> = 
 <a href="arytm_0.html#K2" target="_self">*</a> <font color="Maroon">x</font>,<span class="p1">(<span class="default"><a href="arytm_0.html#K2" target="_self">*</a> <font color="Maroon">y</font>,<span class="p2">(<span class="default"><a href="arytm_0.html#K4" target="_self">inv</a> <font color="Maroon">y</font></span>)</span></span>)</span>
<b>by </b><i><a class="ref" href="arytm_0.html#T4" target="_self">Th4</a></i>
<br/>.= 
 <a href="arytm_0.html#K2" target="_self">*</a> <font color="Maroon">x</font>,<font color="Maroon">j</font>
<b>by </b><i>, <a class="txt" href="arytm_0.html#E1:25"><i><font color="Green">E13</font></i></a></i>
<br/>.= 
<font color="Maroon">x</font>
<b>by </b><i/>
;<br/>


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