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<b>let </b><font color="Maroon" title="c1">G</font> be   <a href="glib_000.html#NM2" title="GLIB_000:NM.2">_Graph</a>;<br/><b>let </b><font color="Maroon" title="c2">x</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/>



<b>consider </b><font color="Maroon" title="c3">v</font> being   <a href="glib_000.html#NM10" title="GLIB_000:NM.10">Vertex</a> of <font color="Maroon" title="c1">G</font>;<br/>
<b>assume </b><a NAME="E2:82"/>
<font color="Maroon" title="c1">G</font> <a href="glib_002.html#R1" title="GLIB_002:pred.1">is_DTree_rooted_at</a> <font color="Maroon" title="c2">x</font>
 ;<br/>

<b>then consider </b><font color="Maroon" title="c4">W</font> being   <a href="glib_001.html#NM6" title="GLIB_001:NM.6">DWalk</a> of <font color="Maroon" title="c1">G</font><b> such that </b><br/><a NAME="E4:82"/><i><font color="Green" title="E49">A1</font></i>: 
<font color="Maroon" title="c4">W</font> <a href="glib_001.html#R1" title="GLIB_001:pred.1">is_Walk_from</a> <font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c3">v</font>
 <b>by </b><i><a class="ref" href="glib_002.html#D4" target="_self" title="GLIB_002:def.4">Def4</a></i>;<br/>
<b>thus </b><a NAME="E5:82"/>
<font color="Maroon" title="c2">x</font> is   <a href="glib_000.html#NM10" title="GLIB_000:NM.10">Vertex</a> of <font color="Maroon" title="c1">G</font>
 <b>by </b><i><a class="txt" href="glib_002.html#E4:82"><i><font color="Green" title="E49">A1</font></i></a>, <a class="ref" href="glib_001.html#T19" title="GLIB_001:th.19">GLIB_001:19</a></i>;<br/>


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