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