| (a ' + x0)[m] = (a ' + x0)[n], m ≤ # x0, n ≤ # x0 ⊦ m = n, dups(x0), a ∈ x0, ∃ m, n. m < # x0 ∧ n < # x0 ∧ m ≠ n ∧ x0[m] = x0[n], m -1 < # x0 ∧ n -1 < # x0 ∧ m -1 ≠ n -1 ∧ x0[m -1] = x0[n -1] |
(a ' + x0)[m] = (a ' + x0)[n], n ≤ # x0, m ≤ # x0 ⊦ m = n, dups(x0), a ∈ x0, ∃ m, n. m < # x0 ∧ n < # x0 ∧ m ≠ n ∧ x0[m] = x0[n], m - 1 < # x0 ∧ n - 1 < # x0 ∧ m - 1 ≠ n - 1 ∧ x0[m - 1] = x0[n - 1]
Used simplifier rules: ⊦ n -1 = n - 1; (s)