| #oc(a, x0) ≤ #oc(a, y0) + #oc(a, z), # y0 + # z < # x0, ∀ a0. #oc(a0, x0) ≤ #oc(a0, y0) + #oc(a0, z) ⊦ x0 = [], #(y0 + z) < # x0 ∧ (∀ a. #oc(a, x0) ≤ #oc(a, y0 + z)), ∃ y. # y < # x0 ∧ (∀ a. #oc(a, x0) ≤ #oc(a, y)) |
#oc(a0, y0) + #oc(a0, z) < #oc(a0, x0), # y0 + # z < # x0, #oc(a, x0) ≤ #oc(a, y0) + #oc(a, z), ∀ a0. #oc(a0, x0) ≤ #oc(a0, y0) + #oc(a0, z) ⊦ x0 = [], ∃ y. # y < # x0 ∧ (∀ a. #oc(a, x0) ≤ #oc(a, y))
Used simplifier rules: ocappend: ⊦ #oc(a, x + y) = #oc(a, x) + #oc(a, y);%f: ⊦ m < n → n ≠ 0; from specification nat-basic1%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%lels-01: ⊦ ¬ m ≤ n ↔ n < m; from specification nat%a: ⊦ (x + y) + z = x + y + z; from specification list%len: ⊦ #(x + y) = # x + # y; from specification list