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<b>let </b><font color="Maroon">c<sub>1</sub></font>, <font color="Maroon">c<sub>2</sub></font> be   <a href="glib_000.html#NM2">_Graph</a>;<br/>



<b>assume </b><a NAME="E1:78"/><i><font color="Green">E47</font></i>: 
( <font color="Maroon">c<sub>1</sub></font> <a href="glib_000.html#R5">==</a> <font color="Maroon">c<sub>2</sub></font> &amp; <font color="Maroon">c<sub>1</sub></font> is <a href="glib_002.html#V2" target="_self">acyclic</a> )
 ;<br/>

<b>then reconsider </b><font color="Maroon">c<sub>3</sub></font> = <font color="Maroon">c<sub>1</sub></font> as  <a href="glib_002.html#V2" target="_self">acyclic</a> <a href="glib_000.html#NM2">_Graph</a> ;<br/>
<a NAME="E3:78"/>
<font color="Maroon">c<sub>2</sub></font> is    <a href="glib_000.html#M2">Subgraph</a> of <font color="Maroon">c<sub>3</sub></font>
 
<b>by </b><i><a class="txt" href="glib_002.html#E1:78"><i><font color="Green">E47</font></i></a>, <a class="ref" href="glib_000.html#T90">GLIB_000:90</a></i>;<br/>
<b>hence </b><a NAME="E4:78"/>
<font color="Maroon">c<sub>2</sub></font> is <a href="glib_002.html#V2" target="_self">acyclic</a>
 ;<br/>


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