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