| ∀ x. disj(x, rev(y0)) ↔ disj(x, y0) ⊦ disj(x, rev(a + y0)) ↔ disj(x, a + y0) |
∀ x. disj(x, rev(y0)) ↔ disj(x, y0) ⊦ disj(x, rev(y0) + a ') ↔ disj(x, a ' + y0)
Used simplifier rules: rev-app: ⊦ rev(x + y) = rev(y) + rev(x);%rev-one: ⊦ rev(a ') = a ';%a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ a + x = a ' + x; (s)