m < n ⊦ n = 0, ∃ m0. m + m0 = n ∧ m0 ≠ 0
Used simplifier rules: l-01: ⊦ m < m + n ↔ n ≠ 0;%a: ⊦ (m + n0) + n1 = m + n0 + n1;%c: ⊦ m + n = n + m;%f: ⊦ m < n → n ≠ 0;