| a ∈ y, ∀ a, y. a ∈ y → rmdup(a ' + x0 + y) = rmdup(x0 + y) ⊦ rmdup(a ' + (a0 ' + x0) + y) = rmdup((a0 ' + x0) + y) |
Used simplifier rules: rmdup-y: ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x);%rmdup-n: ⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x);%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ a + x = a ' + x; (s)% ⊦ x = y + x ↔ y = []; (s)% ⊦ a ' ≠ []; (s)% ⊦ a ∈ y → a ∈ x + y; (s) Used formulas: a ∈ (a0 ' + x0) + y