i→n(i) = m + 1, 0 < n→i(n) + i, n→i(m) < i, n→i(m) + 1 < i, 0 < i ⊦ i = 0
Used simplifier rules: abs-zero: ⊦ i→n(i) = 0 ↔ i = 0;% ⊦ i ≠ j → (i ≤ j ↔ i < j); (s)