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

<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="relat_1.html#NM1">Relation</a>;<br/>

<b>assume </b><a NAME="E1:76_5_1"/><i><font color="Green">E64</font></i>: 
for <font color="Olive">b<sub>1</sub></font>, <font color="Olive">b<sub>2</sub></font> being   <a href="hidden.html#M1">set</a>  st <font color="Olive">b<sub>1</sub></font> <a href="rewrite1.html#R3" target="_self">is_a_normal_form_wrt</a> <font color="Maroon">c<sub>1</sub></font> &amp; <font color="Olive">b<sub>1</sub></font>,<font color="Olive">b<sub>2</sub></font> <a href="rewrite1.html#R2" target="_self">are_convertible_wrt</a> <font color="Maroon">c<sub>1</sub></font> holds <br/><font color="Maroon">c<sub>1</sub></font> <a href="rewrite1.html#R1" target="_self">reduces</a> <font color="Olive">b<sub>2</sub></font>,<font color="Olive">b<sub>1</sub></font>
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="rewrite1.html#D20" target="_self">REWRITE1:def 20</a><br/>

<b>let </b><font color="Maroon">c<sub>2</sub></font>, <font color="Maroon">c<sub>3</sub></font> be    <a href="hidden.html#M1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="rewrite1.html#D19" target="_self">REWRITE1:def 19</a><br/>

<b>assume </b><b>that </b><br/><a NAME="E2:76_5_1"/><i><font color="Green">E65</font></i>: 
( <font color="Maroon">c<sub>2</sub></font> <a href="rewrite1.html#R3" target="_self">is_a_normal_form_wrt</a> <font color="Maroon">c<sub>1</sub></font> &amp; <font color="Maroon">c<sub>3</sub></font> <a href="rewrite1.html#R3" target="_self">is_a_normal_form_wrt</a> <font color="Maroon">c<sub>1</sub></font> )
 <b>and </b><br/><a NAME="E3:76_5_1"/><i><font color="Green">E66</font></i>: 
<font color="Maroon">c<sub>2</sub></font>,<font color="Maroon">c<sub>3</sub></font> <a href="rewrite1.html#R2" target="_self">are_convertible_wrt</a> <font color="Maroon">c<sub>1</sub></font>
 ;<br/>

<a NAME="E4:76_5_1"/>
<font color="Maroon">c<sub>1</sub></font> <a href="rewrite1.html#R1" target="_self">reduces</a> <font color="Maroon">c<sub>3</sub></font>,<font color="Maroon">c<sub>2</sub></font>
 
<b>by </b><i><a class="txt" href="rewrite1.html#E1:76_5_1"><i><font color="Green">E64</font></i></a>, <a class="txt" href="rewrite1.html#E2:76_5_1"><i><font color="Green">E65</font></i></a>, <a class="txt" href="rewrite1.html#E3:76_5_1"><i><font color="Green">E66</font></i></a></i>;<br/>
<b>hence </b><a NAME="E5:76_5_1"/>
<font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> <font color="Maroon">c<sub>3</sub></font>
 <b>by </b><i><a class="txt" href="rewrite1.html#E2:76_5_1"><i><font color="Green">E65</font></i></a>, <a class="ref" href="rewrite1.html#T34" target="_self">Th34</a></i>;<br/>


</div>
