| ∀ a0. a0 ∈ a + x0 ↔ a0 ∈ y, ∀ y. (∀ a. a ∈ x0 ↔ a ∈ y) → # rmdup(x0) = # rmdup(y) ⊦ # rmdup(a + x0) = # rmdup(y) |
∀ y. (∀ a. a ∈ x0 ↔ a ∈ y) → # rmdup(x0) = # rmdup(y), ∀ a0. a0 ∈ a ' + x0 ↔ a0 ∈ y ⊦ # rmdup(a ' + x0) = # rmdup(y)
Used simplifier rules: ⊦ a + x = a ' + x; (s)