1 | 6. i:Vertices(the_graph), s1,s2:traversal(the_graph).
( j:Vertices(the_graph). i-the_graph- > *j  non-trivial-loop(the_graph;j))

depthfirst(the_obj) = (s1 @ [inl(i)] @ s2)

( j:Vertices(the_graph). j = i  i-the_graph- > *j  (inl(j) s2)) 7. i:Vertices(the_graph). (inr(i) depthfirst(the_obj)) & (inl(i) depthfirst(the_obj)) 8. non-trivial-loop-free(the_graph) 9. i: Vertices(the_graph) 10. j: Vertices(the_graph) 11. i-the_graph- > *j 12. i = j 13. (inr(i) depthfirst(the_obj)) 14. (inl(i) depthfirst(the_obj)) 15. s1: (Vertices(the_graph)+Vertices(the_graph)) List 16. s2: (Vertices(the_graph)+Vertices(the_graph)) List 17. depthfirst(the_obj) = (s1 @ [inl(i) / s2]) (Vertices(the_graph)+Vertices(the_graph)) List 18. j1: Vertices(the_graph) 19. i-the_graph- > *j1 non-trivial-loop(the_graph;j1) | 1 step |
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2 | 6. i:Vertices(the_graph), s1,s2:traversal(the_graph).
( j:Vertices(the_graph). i-the_graph- > *j  non-trivial-loop(the_graph;j))

depthfirst(the_obj) = (s1 @ [inl(i)] @ s2)

( j:Vertices(the_graph). j = i  i-the_graph- > *j  (inl(j) s2)) 7. i:Vertices(the_graph). (inr(i) depthfirst(the_obj)) & (inl(i) depthfirst(the_obj)) 8. non-trivial-loop-free(the_graph) 9. i: Vertices(the_graph) 10. j: Vertices(the_graph) 11. i-the_graph- > *j 12. i = j 13. (inr(i) depthfirst(the_obj)) 14. (inl(i) depthfirst(the_obj)) 15. s1: (Vertices(the_graph)+Vertices(the_graph)) List 16. s2: (Vertices(the_graph)+Vertices(the_graph)) List 17. depthfirst(the_obj) = (s1 @ [inl(i) / s2]) (Vertices(the_graph)+Vertices(the_graph)) List j = i | 1 step |
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3 | 6. i:Vertices(the_graph), s1,s2:traversal(the_graph).
( j:Vertices(the_graph). i-the_graph- > *j  non-trivial-loop(the_graph;j))

depthfirst(the_obj) = (s1 @ [inl(i)] @ s2)

( j:Vertices(the_graph). j = i  i-the_graph- > *j  (inl(j) s2)) 7. i:Vertices(the_graph). (inr(i) depthfirst(the_obj)) & (inl(i) depthfirst(the_obj)) 8. non-trivial-loop-free(the_graph) 9. i: Vertices(the_graph) 10. j: Vertices(the_graph) 11. i-the_graph- > *j 12. i = j 13. (inr(i) depthfirst(the_obj)) 14. (inl(i) depthfirst(the_obj)) 15. s1: (Vertices(the_graph)+Vertices(the_graph)) List 16. s2: (Vertices(the_graph)+Vertices(the_graph)) List 17. depthfirst(the_obj) = (s1 @ [inl(i) / s2]) (Vertices(the_graph)+Vertices(the_graph)) List 18. (inl(j) s2) inl(i) before inl(j) depthfirst(the_obj) | 2 steps |