i→n(i) + n < m, 0 ≤ i, n→i(m) ≤ i + n→i(n) ⊦ m = 0
Used simplifier rules: f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%lels: ⊦ ¬ i < j ↔ j ≤ i; from specification int-abs