| n = m + 1, n ≤ # x0, ∀ n0. n0 < # x0 → pos(x0[n0], x0) = n0 ∨ x0 = [] ⊦ n = 0, pos(x0[m], a ' + x0) = n, dups(x0), a ∈ x0 |
m < # x0, ∀ n. n < # x0 → pos(x0[n], x0) = n ⊦ pos(x0[m], a ' + x0) = m + 1, x0 = [], dups(x0), a ∈ x0
Used simplifier rules: ⊦ # x = 0 ↔ x = []; (s)%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic% ⊦ m + 1 ≤ n ↔ m < n; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m + 1 ≠ 0; (s)