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<b>let </b><font color="Maroon" title="c1">R</font> be   <a href="relat_1.html#NM1" title="RELAT_1:NM.1">Relation</a>;<br/>

<b>assume </b><a NAME="E1:76_5_1"/><i><font color="Green" title="E64">A15</font></i>: 
for <font color="Olive" title="b1">a</font>, <font color="Olive" title="b2">b</font> being   <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a>   st <font color="Olive" title="b1">a</font> <a href="rewrite1.html#R3" title="REWRITE1:pred.3">is_a_normal_form_wrt</a> <font color="Maroon" title="c1">R</font> &amp; <font color="Olive" title="b1">a</font>,<font color="Olive" title="b2">b</font> <a href="rewrite1.html#R2" title="REWRITE1:pred.2">are_convertible_wrt</a> <font color="Maroon" title="c1">R</font> holds <br/><font color="Maroon" title="c1">R</font> <a href="rewrite1.html#R1" title="REWRITE1:pred.1">reduces</a> <font color="Olive" title="b2">b</font>,<font color="Olive" title="b1">a</font>
 ; <i><font color="Red">:: according to </font></i><a class="ref" href="rewrite1.html#D20" target="_self" title="REWRITE1:def.20">REWRITE1:def 20</a><br/>

<b>let </b><font color="Maroon" title="c2">a</font>, <font color="Maroon" title="c3">b</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ; <i><font color="Red">:: according to </font></i><a class="ref" href="rewrite1.html#D19" target="_self" title="REWRITE1:def.19">REWRITE1:def 19</a><br/>

<b>assume </b><b>that </b><br/><a NAME="E2:76_5_1"/><i><font color="Green" title="E65">A16</font></i>: 
( <font color="Maroon" title="c2">a</font> <a href="rewrite1.html#R3" title="REWRITE1:pred.3">is_a_normal_form_wrt</a> <font color="Maroon" title="c1">R</font> &amp; <font color="Maroon" title="c3">b</font> <a href="rewrite1.html#R3" title="REWRITE1:pred.3">is_a_normal_form_wrt</a> <font color="Maroon" title="c1">R</font> )
 <b>and </b><br/><a NAME="E3:76_5_1"/><i><font color="Green" title="E66">A17</font></i>: 
<font color="Maroon" title="c2">a</font>,<font color="Maroon" title="c3">b</font> <a href="rewrite1.html#R2" title="REWRITE1:pred.2">are_convertible_wrt</a> <font color="Maroon" title="c1">R</font>
 ;<br/>

<a NAME="E4:76_5_1"/>
<font color="Maroon" title="c1">R</font> <a href="rewrite1.html#R1" title="REWRITE1:pred.1">reduces</a> <font color="Maroon" title="c3">b</font>,<font color="Maroon" title="c2">a</font>
 
<b>by </b><i><a class="txt" href="rewrite1.html#E1:76_5_1"><i><font color="Green" title="E64">A15</font></i></a>, <a class="txt" href="rewrite1.html#E2:76_5_1"><i><font color="Green" title="E65">A16</font></i></a>, <a class="txt" href="rewrite1.html#E3:76_5_1"><i><font color="Green" title="E66">A17</font></i></a></i>;<br/>
<b>hence </b><a NAME="E5:76_5_1"/>
<font color="Maroon" title="c2">a</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c3">b</font>
 <b>by </b><i><a class="txt" href="rewrite1.html#E2:76_5_1"><i><font color="Green" title="E65">A16</font></i></a>, <a class="ref" href="rewrite1.html#T34" target="_self" title="REWRITE1:th.34">Th34</a></i>;<br/>


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