n0 < m, ∀ m. n0 = m ∨ m < n0 ∨ n0 < m ⊦ n0 +1 = m, m = 0, n0 +1 < m
Used simplifier rules: ls-02: ⊦ m < n → ¬ n < m;%f: ⊦ m < n → n ≠ 0;