1 | 1. G: Graph 2. x,y:Vertices(G). Dec(x = y) 3. s: traversal(G) 4. paren(Vertices(G);s) 5. no_repeats(Vertices(G)+Vertices(G);s) 6. i:Vertices(G), s1,s2:traversal(G).
s = (s1 @ [inr(i)] @ s2) traversal(G)

( j:Vertices(G). (inr(j) s2)  (inl(j) s2)  j-G- > *i) 7. i:Vertices(G), s1,s2:traversal(G).
( j:Vertices(G). i-G- > *j  non-trivial-loop(G;j))

s = (s1 @ [inl(i)] @ s2) traversal(G)  ( j:Vertices(G). i-G- > *j  (inr(j) s2)) 8. i: Vertices(G) 9. s1: traversal(G) 10. s2: traversal(G) 11. j:Vertices(G). i-G- > *j  non-trivial-loop(G;j) 12. s = (s1 @ [inl(i)] @ s2) traversal(G) 13. j: Vertices(G) 14. j = i 15. i-G- > *j 16. (inr(j) s2) 17. (inl(j) s2) (inl(j) s2) | 17 steps |