| ¬ a ∈ z, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦ (a ' + rmdup(y0)) \ z = rmdup(a + (y0 \ z)), a ∈ y0 |
∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦ a ' + (rmdup(y0) \ z) = rmdup(a ' + (y0 \ z)), a ∈ y0, a ∈ z
Used simplifier rules: diff-n: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y);%a: ⊦ (x + y) + z = x + y + z; from specification list%c: ⊦ a + x = a ' + x; from specification list