| n = n0 + # x, # x < n, # x ≤ n ⊦ x + y from n = y from n0 |
⊦ x + y from n0 + # x = y from n0, n0 = 0
Used simplifier rules: c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m < m + n ↔ n ≠ 0; (s)% ⊦ m < n → m ≤ n; (s)