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