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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>, <font color="Maroon" title="c3">e</font>, <font color="Maroon" title="c4">y</font> be    <a href="hidden.html#M1" title="HIDDEN:mode.1">set</a> ;<br/><b>let </b><font color="Maroon" title="c5">v1</font> be   <a href="glib_000.html#NM10" title="GLIB_000:NM.10">Vertex</a> of <font color="Maroon" title="c1">G</font>;<br/>









<b>set </b><font color="Maroon" title="c6">RFV</font> = <font color="Maroon" title="c1">G</font> <a href="glib_002.html#K2" title="GLIB_002:func.2">.reachableDFrom</a> <font color="Maroon" title="c5">v1</font>;<br/>
<b>assume </b><a NAME="E1:68"/><i><font color="Green" title="E43">A1</font></i>: 
( <font color="Maroon" title="c2">x</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">G</font> <a href="glib_002.html#K2" title="GLIB_002:func.2">.reachableDFrom</a> <font color="Maroon" title="c5">v1</font> &amp; <font color="Maroon" title="c3">e</font> <a href="glib_000.html#R2" title="GLIB_000:pred.2">DJoins</a> <font color="Maroon" title="c2">x</font>,<font color="Maroon" title="c4">y</font>,<font color="Maroon" title="c1">G</font> )
 ;<br/>

<b>then consider </b><font color="Maroon" title="c7">W</font> being  <a href="glib_001.html#V2" title="GLIB_001:attr.2">directed</a>  <a href="glib_001.html#M3" title="GLIB_001:mode.3">Walk</a> of <font color="Maroon" title="c1">G</font><b> such that </b><br/><a NAME="E3:68"/><i><font color="Green" title="E44">A2</font></i>: 
<font color="Maroon" title="c7">W</font> <a href="glib_001.html#R1" title="GLIB_001:pred.1">is_Walk_from</a> <font color="Maroon" title="c5">v1</font>,<font color="Maroon" title="c2">x</font>
 <b>by </b><i><a class="ref" href="glib_002.html#D6" target="_self" title="GLIB_002:def.6">Def6</a></i>;<br/>
<a NAME="E4:68"/>
( <font color="Maroon" title="c7">W</font> <a href="glib_001.html#K10" title="GLIB_001:func.10">.addEdge</a> <font color="Maroon" title="c3">e</font> is <a href="glib_001.html#V2" title="GLIB_001:attr.2">directed</a> &amp; <font color="Maroon" title="c7">W</font> <a href="glib_001.html#K10" title="GLIB_001:func.10">.addEdge</a> <font color="Maroon" title="c3">e</font> <a href="glib_001.html#R1" title="GLIB_001:pred.1">is_Walk_from</a> <font color="Maroon" title="c5">v1</font>,<font color="Maroon" title="c4">y</font> )
 
<b>by </b><i><a class="txt" href="glib_002.html#E1:68"><i><font color="Green" title="E43">A1</font></i></a>, <a class="txt" href="glib_002.html#E3:68"><i><font color="Green" title="E44">A2</font></i></a>, <a class="ref" href="glib_001.html#T124" title="GLIB_001:th.124">GLIB_001:124</a></i>;<br/>
<b>hence </b><a NAME="E5:68"/>
<font color="Maroon" title="c4">y</font> <a href="hidden.html#R2" title="HIDDEN:pred.2">in</a> <font color="Maroon" title="c1">G</font> <a href="glib_002.html#K2" title="GLIB_002:func.2">.reachableDFrom</a> <font color="Maroon" title="c5">v1</font>
 <b>by </b><i><a class="ref" href="glib_002.html#D6" target="_self" title="GLIB_002:def.6">Def6</a></i>;<br/>


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