| a0 ∈ x0, ∀ a. a ∈ x0 → a ∈ rmdup(x0), a = a0 ∨ a ∈ x0 ⊦ a ∈ rmdup(a0 ' + x0) |
a0 ∈ x0, a ∈ x0, ∀ a. a ∈ x0 → a ∈ rmdup(x0) ⊦ a ∈ rmdup(x0)
Used simplifier rules: rmdup-y: ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x);%a: ⊦ (x + y) + z = x + y + z; from specification list