| n0 = 0, H[r].nxt ∈ H, r ∈ H, reachable-n(H, n0, H[r].nxt, r0), n0 = 0 ∨ path(H[r].nxt ' + x, H) ∧ (H[r].nxt ' + x).last = r0 ⊦ H[r].nxt = null, r = null, ∃ x. path(r ' + x, H) ∧ (r ' + x).last = r0 |
r ∈ H, H[r].nxt ∈ H ⊦ r = null, H[r].nxt = null, ∃ x. path(r ' + x, H) ∧ (r ' + x).last = H[r].nxt
Used simplifier rules: reachable-n-base: ⊦ reachable-n(H, 0, r, r0) ↔ r = r0;