<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon" title="c2">c1</font>, <font color="Maroon" title="c3">c2</font> be   <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">L</font>;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:30_1_2"/><i><font color="Green" title="E13">A2</font></i>: 
for <font color="Olive" title="b1">a</font> being  <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">L</font> holds  <font color="Maroon" title="c2">c1</font> <a href="robbins1.html#K6" title="ROBBINS1:func.6">*'</a> <font color="Olive" title="b1">a</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">c1</font>
 <b>and </b><br/><a NAME="E2:30_1_2"/><i><font color="Green" title="E14">A3</font></i>: 
for <font color="Olive" title="b1">a</font> being  <a href="struct_0.html#NM1" title="STRUCT_0:NM.1">Element</a> of <font color="Maroon" title="c1">L</font> holds  <font color="Maroon" title="c3">c2</font> <a href="robbins1.html#K6" title="ROBBINS1:func.6">*'</a> <font color="Olive" title="b1">a</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">c2</font>
 ;<br/>

<b>thus </b><font color="Maroon" title="c2">c1</font> = 
<font color="Maroon" title="c3">c2</font> <a href="robbins1.html#K6" title="ROBBINS1:func.6">*'</a> <font color="Maroon" title="c2">c1</font>
<b>by </b><i><a class="txt" href="robbins1.html#E1:30_1_2"><i><font color="Green" title="E13">A2</font></i></a></i>
<br/>.= 
<font color="Maroon" title="c3">c2</font>
<b>by </b><i><a class="txt" href="robbins1.html#E2:30_1_2"><i><font color="Green" title="E14">A3</font></i></a></i>
;<br/>


</div>
