m1 < m2 ⊦ m2 * m ≤ m1 * m + n0 ↔ (m2 - m1) * m ≤ n0
Used simplifier rules: ⊦ m < n → n ≠ 0; (s)%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic