| n0 +1 < # x, ∀ x. n0 < # x → x[n0, x[n0]] = x ∨ x = [] ⊦ x[n0 +1, x[n0 +1]] = x, x = [] |
n0 + 1 < # x, ∀ x. n0 < # x → x[n0, x[n0]] = x ∨ x = [] ⊦ x[n0 + 1, x.tail[n0]] = x, x = []
Used simplifier rules: get-rec-01: ⊦ x ≠ [] → x[n + 1] = x.tail[n];%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m +1 = m + 1; (s)