| (r ' + x1)[m] = (r ' + x1)[n], n < m, path(r ' + x1, H), m ≤ # x1, n < # x1 ⊦ n = 0, m = n, x1 = [], reachable-n(H, n, r, (r ' + x1)[n]), path(r ' + firstn(n, x1), H) ∧ firstn(n, x1) .last = (r ' + x1)[n] |
⊦ m ≠ 0 ∧ m ≤ # x0 → firstn(m, x0) .last = x0[m -1]
n ≠ 0 ∧ n ≤ # x1, (r ' + x1)[m] = (r ' + x1)[n], n < m, path(r ' + x1, H), m ≤ # x1, n < # x1 ⊦ n = 0, m = n, x1 = [], reachable-n(H, n, r, (r ' + x1)[n]), path(r ' + firstn(n, x1), H) ∧ x1[n -1] = (r ' + x1)[n]
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ m < n → m ≤ n])], [EXTRATERMS : (x1, n)]]