| # x = n0 + n1 ⊦ # butlastn(n0, x) = n1 |
⊦ n ≤ # x → # butlastn(n, x) = # x - n
Used simplifier rules: eq-01: ⊦ m + n - m = n; from specification nat%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2%c: ⊦ m + n = n + m; from specification nat-basic2%lels-01: ⊦ ¬ m ≤ n ↔ n < m; from specification nat%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%lf-02: ⊦ m < n ∧ m = n0 → n0 < n; (forward) from specification nat-basic1%l-02: ⊦ ¬ m + n < m; from specification nat-basic2 Used terms: x, n0