| a ∈ x0, n ≤ # x0, ∀ n0, a1. n0 < # x0 → (a1 ∈ x0 -p n0 ↔ a1 ≠ x0[n0] ∧ a1 ∈ x0) ⊦ a = x0[n - 1], n = 0, x0 = [], dups(x0), a ∈ (a0 ' + x0) -p n, a0 ∈ x0 |
n = m + 1, a ∈ x0, n ≤ # x0, ∀ n0, a1. n0 < # x0 → (a1 ∈ x0 -p n0 ↔ a1 ≠ x0[n0] ∧ a1 ∈ x0) ⊦ a = x0[m], n = 0, x0 = [], dups(x0), a0 ∈ x0, a ∈ (a0 ' + x0) -p n
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: n, m