| n ≤ # x0, ∀ n, y, a. n < # x0 → (x0 + y)[n, a] = x0[n, a] + y ⊦ n = 0, a0 ' + (x0 + y)[n - 1, a] = (a0 ' + x0)[n, a] + y |
n = m + 1, n ≤ # x0, ∀ n, y, a. n < # x0 → (x0 + y)[n, a] = x0[n, a] + y ⊦ n = 0, a0 ' + (x0 + y)[m, a] = (a0 ' + x0)[n, a] + y
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: n, m