| n ≤ # x0, ∀ n. n < # x0 → restn(n, x0).last = x0.last ⊦ restn(n, a ' + x0).last = (a ' + x0).last, x0 = [] |
n ≤ # x0, ∀ n. n < # x0 → restn(n, x0).last = x0.last ⊦ restn(n, a ' + x0).last = x0.last, x0 = []
Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ x ≠ [] → (a ' + x).last = x.last; (s)