| ¬ a ∈ x0 + y, ∀ y. rmdup(x0 + rmdup(y)) = rmdup(x0 + y) ⊦ a ' + rmdup(x0 + rmdup(y)) = a + rmdup(x0 + y), a ∈ x0, a ∈ y |
∀ y. rmdup(x0 + rmdup(y)) = rmdup(x0 + y) ⊦ rmdup(x0 + rmdup(y)) = rmdup(x0 + y), a ∈ x0, a ∈ y
Used simplifier rules: in-append: ⊦ a ∈ x + y ↔ ¬ ¬(a ∈ x ∨ a ∈ y); from specification list%a: ⊦ (x + y) + z = x + y + z; from specification list%app-08: ⊦ a ' + x = a ' + y ↔ x = y; from specification list%c: ⊦ a + x = a ' + x; from specification list