| ⊦ m -1 -1 +1 = m -1, m = 1, m = 0 |
Used simplifier rules: succ: ⊦ m +1 = m + 1;%pse: ⊦ n ≠ 0 ∧ n ≠ 1 → m + n -1 -1 = (m + n)-1 -1;%pred: ⊦ (m + 1)-1 = m;%a: ⊦ (m + n0) + n1 = m + n0 + n1;%c: ⊦ m + n = n + m;%psh-03: ⊦ m ≠ 0 → (m -1 = n ↔ m = n +1);%psu: ⊦ m ≠ 0 → m -1 +1 = m;