| path(H[r].nxt ' + x0, H), r ∈ H, ∀ r0, H0. path(r0 ' + x0, H0) → r0 = null ∨ (∃ n. reachable-n(H0, n, r0, x0.last)) ⊦ x0 = [], r = null, ∃ n. reachable-n(H, n, r, x0.last) |
path(H[r].nxt ' + x0, H), r ∈ H, path(H[r].nxt ' + x0, H) → H[r].nxt = null ∨ (∃ n. reachable-n(H, n, H[r].nxt, x0.last)) ⊦ x0 = [], r = null, ∃ n. reachable-n(H, n, r, x0.last)
Used terms: H[r].nxt, H