| (r ' + x1)[m] = (r ' + x1)[n], n < m, path(r ' + x1, H), m ≤ # x1, n < # x1 ⊦ m = n, x1 = [], n = 0, reachable-n(H, n, r, (r ' + x1)[n]), path(r ' + firstn(n, x1), H) ∧ x1[n - 1] = (r ' + x1)[n] |
n = m0 + 1, (r ' + x1)[m] = (r ' + x1)[n], n < m, path(r ' + x1, H), m ≤ # x1, n < # x1 ⊦ m = n, x1 = [], n = 0, reachable-n(H, n, r, (r ' + x1)[n]), path(r ' + firstn(n, x1), H) ∧ x1[m0] = (r ' + x1)[n]
[[CONCRETESIMPRULES : ([CSIMPELIM : n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1])], [EXTRATERMS : (n, m0)]]