| x = [], path(r ' + x, H) ⊦ r = null, ∃ n. reachable-n(H, n, r, (r ' + x).last) |
r ∈ H ⊦ r = null, ∃ n. reachable-n(H, n, r, r)
Used simplifier rules: path-one: ⊦ path(r ', H) ↔ r ∈ H ∧ r ≠ null;% ⊦ r '.last = r; (s)%a: ⊦ (x0 + x1) + x2 = x0 + x1 + x2; from specification list[reflist]% ⊦ x0 + [] = x0; (s)