| ∀ a, n. rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ n = 0 ∨ a ∈ x0 ⊦ n = 0, (a0 ∈ x0 + mklist(a, n) ⊃ rmdup(x0 + mklist(a, n));a0 ' + rmdup(x0 + mklist(a, n))) = rmdup(a0 ' + x0) + a ', a = a0, a ∈ x0 |
∀ a, n. rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ n = 0 ∨ a ∈ x0 ⊦ a = a0, n = 0, (a0 ∈ x0 ∨ a0 ∈ mklist(a, n) ⊃ rmdup(x0 + mklist(a, n));a0 ' + rmdup(x0 + mklist(a, n))) = rmdup(a0 ' + x0) + a ', a ∈ x0
Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification list%in-append: ⊦ a ∈ x + y ↔ ¬ ¬(a ∈ x ∨ a ∈ y); from specification list