| reachable-n(H, # H + 1, r, r0), ∀ n. ∃ r0. reachable-n(H, n, r, r0) ⊦ cyclic(r, H) |
⊦ n ≠ 0 → (reachable-n(H, n, r, r0) ↔ (∃ x. path(x, H) ∧ hd x = r ∧ x .last = r0 ∧ # x = n + 1))
# H + 1 ≠ 0, ∃ x. path(x, H) ∧ hd x = r ∧ x .last = r0 ∧ # x = (# H + 1) + 1, ∀ n. ∃ r0. reachable-n(H, n, r, r0) ⊦ cyclic(r, H)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ m + 1 ≠ 0], [CSIMPSEQ : ⊦ (m + n0) + n1 = m + n0 + n1], [CSIMPSEQ : ⊦ m + n = n + m])], [EXTRATERMS : (r0, r, # H + 1, H)]]