| 1 | 28. x: Vertices(the_graph) 29. v: (Vertices(the_graph)+Vertices(the_graph)) List 30. s = ([inl(x) / v] @ s1) traversal(the_graph) 31. paren(Vertices(the_graph);s1) 32. paren(Vertices(the_graph);[inl(x) / v]) 33. j:Vertices(the_graph). (inl(j) s1)  L1-the_graph- > *j 34. j:Vertices(the_graph). (inl(j) [inl(x) / v])  nil-the_graph- > *j & L1-the_graph- > *j 35. j:Vertices(the_graph). (inl(j) [inl(x) / v])  False 36. j:Vertices(the_graph). (inr(j) [inl(x) / v])  False [inl(x) / v] = nil traversal(the_graph) | 2 steps |
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| 2 | 28. y: Vertices(the_graph) 29. v: (Vertices(the_graph)+Vertices(the_graph)) List 30. s = ([inr(y) / v] @ s1) traversal(the_graph) 31. paren(Vertices(the_graph);s1) 32. paren(Vertices(the_graph);[inr(y) / v]) 33. j:Vertices(the_graph). (inl(j) s1)  L1-the_graph- > *j 34. j:Vertices(the_graph). (inl(j) [inr(y) / v])  nil-the_graph- > *j & L1-the_graph- > *j 35. j:Vertices(the_graph). (inl(j) [inr(y) / v])  False 36. j:Vertices(the_graph). (inr(j) [inr(y) / v])  False [inr(y) / v] = nil traversal(the_graph) | 2 steps |