i:Vertices(the_graph), s1,s2:traversal(the_graph). (j:Vertices(the_graph). i-the_graph- > *j 
non-trivial-loop(the_graph;j)) s = (s1 @ [inl(i)] @ s2) 
traversal(the_graph) (j:Vertices(the_graph). j = i i-the_graph- > *j (inl(j) s2))
is mentioned
In prior sections: graph 1 2 graph 1 3