| n ≤ # x0, ∀ n. n < # x0 → x0[n] ' + (x0 from n + 1) = x0 from n ∨ x0 = [] ⊦ x0[n -1] ' + (x0 from n) = a ' + x0 from n, n = 0 |
n ≤ # x0, ∀ n. n < # x0 → x0[n] ' + (x0 from n + 1) = x0 from n ∨ x0 = [] ⊦ x0[n - 1] ' + (x0 from n) = a ' + x0 from n, n = 0
Used simplifier rules: ⊦ n -1 = n - 1; (s)