| ∀ 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 |
a0 ∈ x0 ∨ a0 ∈ mklist(a, n), ∀ a, n. rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ n = 0 ∨ a ∈ x0 ⊦ rmdup(x0 + mklist(a, n)) = rmdup(a0 ' + x0) + a ', a = a0, n = 0, a ∈ x0
¬(a0 ∈ x0 ∨ a0 ∈ mklist(a, n)), ∀ a, n. rmdup(x0 + mklist(a, n)) = rmdup(x0) + a ' ∨ n = 0 ∨ a ∈ x0 ⊦ a0 ' + rmdup(x0 + mklist(a, n)) = rmdup(a0 ' + x0) + a ', a = a0, n = 0, a ∈ x0