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