| 1 | 18. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inr(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). (inr(j) s2@0)  (inl(j) s2@0)  j-the_graph- > *i@0) 19. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
( j:Vertices(the_graph). i@0-the_graph- > *j  non-trivial-loop(the_graph;j))

(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inl(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). i@0-the_graph- > *j  (inr(j) s2@0)) 20. i@0:Vertices(the_graph). L1 @ [i]-the_graph- > *i@0  non-trivial-loop(the_graph;i@0) 21. L1@0,L2:Vertices(the_graph) List.
L1 = (L1@0 @ L2)

( s1,s2:traversal(the_graph).
s = (s2 @ s1) traversal(the_graph)
& paren(Vertices(the_graph);s1) & paren(Vertices(the_graph);s2)
& ( j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j)
& ((inl(j) s2)  L2-the_graph- > *j & L1@0-the_graph- > *j))) 22. L1@0: Vertices(the_graph) List 23. L2: Vertices(the_graph) List 24. (L1 @ [i]) = (L1@0 @ L2) 25. e: Vertices(the_graph) List 26. L1 = (L1@0 @ e) 27. L2 = (e @ [i]) 28. s1: traversal(the_graph) 29. s3: traversal(the_graph) 30. s = (s3 @ s1) traversal(the_graph) 31. paren(Vertices(the_graph);s1) 32. paren(Vertices(the_graph);s3) 33. j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j) & ((inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j) 34. j: Vertices(the_graph) 35. (inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j 36. (inl(j) s3)  (e-the_graph- > *j & L1@0-the_graph- > *j) 37. i-the_graph- > *j 38. L1@0-the_graph- > *j 39. j1: Vertices(the_graph) 40. i-the_graph- > *j1 non-trivial-loop(the_graph;j1) | 2 steps |
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| 2 | 18. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inr(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). (inr(j) s2@0)  (inl(j) s2@0)  j-the_graph- > *i@0) 19. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
( j:Vertices(the_graph). i@0-the_graph- > *j  non-trivial-loop(the_graph;j))

(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inl(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). i@0-the_graph- > *j  (inr(j) s2@0)) 20. i@0:Vertices(the_graph). L1 @ [i]-the_graph- > *i@0  non-trivial-loop(the_graph;i@0) 21. L1@0,L2:Vertices(the_graph) List.
L1 = (L1@0 @ L2)

( s1,s2:traversal(the_graph).
s = (s2 @ s1) traversal(the_graph)
& paren(Vertices(the_graph);s1) & paren(Vertices(the_graph);s2)
& ( j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j)
& ((inl(j) s2)  L2-the_graph- > *j & L1@0-the_graph- > *j))) 22. L1@0: Vertices(the_graph) List 23. L2: Vertices(the_graph) List 24. (L1 @ [i]) = (L1@0 @ L2) 25. e: Vertices(the_graph) List 26. L1 = (L1@0 @ e) 27. L2 = (e @ [i]) 28. s1: traversal(the_graph) 29. s3: traversal(the_graph) 30. s = (s3 @ s1) traversal(the_graph) 31. paren(Vertices(the_graph);s1) 32. paren(Vertices(the_graph);s3) 33. j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j) & ((inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j) 34. j: Vertices(the_graph) 35. (inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j 36. (inl(j) s3)  (e-the_graph- > *j & L1@0-the_graph- > *j) 37. i-the_graph- > *j 38. L1@0-the_graph- > *j (([inl(i)] @ s2 @ [inr(i)]) @ s) = (nil @ [inl(i)] @ (s2 @ [inr(i)]) @ s) traversal(the_graph) | 1 step |
|   |
| 3 | 18. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inr(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). (inr(j) s2@0)  (inl(j) s2@0)  j-the_graph- > *i@0) 19. i@0:Vertices(the_graph), s1,s2@0:traversal(the_graph).
( j:Vertices(the_graph). i@0-the_graph- > *j  non-trivial-loop(the_graph;j))

(([inl(i)] @ s2 @ [inr(i)]) @ s) = (s1 @ [inl(i@0)] @ s2@0) traversal(the_graph)

( j:Vertices(the_graph). i@0-the_graph- > *j  (inr(j) s2@0)) 20. i@0:Vertices(the_graph). L1 @ [i]-the_graph- > *i@0  non-trivial-loop(the_graph;i@0) 21. L1@0,L2:Vertices(the_graph) List.
L1 = (L1@0 @ L2)

( s1,s2:traversal(the_graph).
s = (s2 @ s1) traversal(the_graph)
& paren(Vertices(the_graph);s1) & paren(Vertices(the_graph);s2)
& ( j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j)
& ((inl(j) s2)  L2-the_graph- > *j & L1@0-the_graph- > *j))) 22. L1@0: Vertices(the_graph) List 23. L2: Vertices(the_graph) List 24. (L1 @ [i]) = (L1@0 @ L2) 25. e: Vertices(the_graph) List 26. L1 = (L1@0 @ e) 27. L2 = (e @ [i]) 28. s1: traversal(the_graph) 29. s3: traversal(the_graph) 30. s = (s3 @ s1) traversal(the_graph) 31. paren(Vertices(the_graph);s1) 32. paren(Vertices(the_graph);s3) 33. j:Vertices(the_graph).
((inl(j) s1)  L1@0-the_graph- > *j) & ((inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j) 34. j: Vertices(the_graph) 35. (inl(j) s3)  e-the_graph- > *j & L1@0-the_graph- > *j 36. (inl(j) s3)  (e-the_graph- > *j & L1@0-the_graph- > *j) 37. i-the_graph- > *j 38. L1@0-the_graph- > *j 39. (inr(j) (s2 @ [inr(i)]) @ s) (inl(j) s2) (inl(j) s) inl(j) = inl(i) Vertices(the_graph)+Vertices(the_graph) | 7 steps |