| ∀ n, a. n = 0 ∨ rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ a ∈ x0 ⊦ n = 0, rmdup((a0 + x0) + mklist(a, n)) = rmdup(a0 + x0) + a ', a ∈ a0 + x0 |
∀ n, a. n = 0 ∨ rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ a ∈ x0 ⊦ a = a0, n = 0, rmdup((a0 ' + x0) + mklist(a, n)) = rmdup(a0 ' + x0) + a ', a ∈ x0
Used simplifier rules: ⊦ a ∈ b ' + x ↔ ¬(a ≠ b ∧ ¬ a ∈ x); (ss)%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ a + x = a ' + x; (s)