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<b>let </b><font color="Maroon">c<sub>1</sub></font> be   <a href="glib_000.html#NM2">_Graph</a>;<br/><b>let </b><font color="Maroon">c<sub>2</sub></font> be    <a href="glib_001.html#M3" target="_self">Walk</a> of <font color="Maroon">c<sub>1</sub></font>;<br/>



<div><b>hereby </b>
<div class="add"><b>assume </b><a NAME="E1:214_1"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="glib_001.html#V3" target="_self">trivial</a>
 ;<br/><a NAME="E2:214_1"/><b>then </b>
 <a href="finseq_1.html#K3">len</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> 1
 <b>by </b><i><a class="txt" href="glib_001.html#E97"><i><font color="Green">Lemma89</font></i></a></i>;<br/><a NAME="E3:214_1"/><b>then </b>
 <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="glib_001.html#K6" target="_self">.reverse()</a> </span>)</span> <a href="hidden.html#R1">=</a> 1
 <b>by </b><i><a class="txt" href="glib_001.html#E46"><i><font color="Green">Lemma38</font></i></a></i>;<br/><b>hence </b><a NAME="E4:214_1"/>
<font color="Maroon">c<sub>2</sub></font> <a href="glib_001.html#K6" target="_self">.reverse()</a>  is <a href="glib_001.html#V3" target="_self">trivial</a>
 <b>by </b><i><a class="txt" href="glib_001.html#E97"><i><font color="Green">Lemma89</font></i></a></i>;<br/></div>
<b>end;</b></div>

<b>assume </b><a NAME="E2:214"/>
<font color="Maroon">c<sub>2</sub></font> <a href="glib_001.html#K6" target="_self">.reverse()</a>  is <a href="glib_001.html#V3" target="_self">trivial</a>
 ;<br/>

<a NAME="E3:214"/><b>then </b>
 <a href="finseq_1.html#K3">len</a> <span class="p1">(<span class="default"><font color="Maroon">c<sub>2</sub></font> <a href="glib_001.html#K6" target="_self">.reverse()</a> </span>)</span> <a href="hidden.html#R1">=</a> 1
 
<b>by </b><i><a class="txt" href="glib_001.html#E97"><i><font color="Green">Lemma89</font></i></a></i>;<br/>
<a NAME="E4:214"/><b>then </b>
 <a href="finseq_1.html#K3">len</a> <font color="Maroon">c<sub>2</sub></font> <a href="hidden.html#R1">=</a> 1
 
<b>by </b><i><a class="txt" href="glib_001.html#E46"><i><font color="Green">Lemma38</font></i></a></i>;<br/>
<b>hence </b><a NAME="E5:214"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="glib_001.html#V3" target="_self">trivial</a>
 <b>by </b><i><a class="txt" href="glib_001.html#E97"><i><font color="Green">Lemma89</font></i></a></i>;<br/>


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