| a ∈ y, a ∈ rmdup(y + z), ∀ y, z. (x0 \ y) \ z = x0 \ rmdup(y + z) ⊦ (x0 \ y) \ z = (a ' + x0) \ rmdup(y + z) |
a ∈ y, a ∈ rmdup(y + z), ∀ y, z. (x0 \ y) \ z = x0 \ rmdup(y + z) ⊦ (x0 \ y) \ z = x0 \ rmdup(y + z)
Used simplifier rules: diff-y: ⊦ a ∈ y → (a ' + x) \ y = x \ y;% ⊦ a ∈ x → a ∈ x + y; (s)%rm-in-01: ⊦ a ∈ rmdup(x) → a ∈ x; (forward) from specification list-dup%a: ⊦ (x + y) + z = x + y + z; from specification list