| m ≤ #(x to n0), n0 < # x, n0 < # x, m ≤ n0 + 1, m ≤ # x, ∀ m, x. m ≤ n0 ∧ n0 ≤ # x ∧ m ≤ # x → x to n0 to m = x to m ⊦ x to n0 to m = x to m, x = [] |
m < # x, m ≤ n0, m ≤ n0 + 1, n0 < # x, ∀ m, x. m ≤ n0 ∧ n0 ≤ # x ∧ m ≤ # x → x to n0 to m = x to m ⊦ x = [], x to n0 to m = x to m
Used simplifier rules: length-to: ¬ # x < n ⊦ #(x to n) = n;%lels-03: ⊦ m < n → m ≤ n; from specification nat%fle-01: ⊦ m ≤ n ∧ n < n0 → m < n0; (forward) from specification nat%ls-02: ⊦ m < n → ¬ n < m; from specification nat-basic1