∀ {R : Type u_1} [inst : CommSemiring R] [inst_1 : TopologicalSpace R] [inst_2 : IsTopologicalSemiring R] (X : Set R)
  (x x_1 : Polynomial R), (x + x_1).toContinuousMapOn X = x.toContinuousMapOn X + x_1.toContinuousMapOn X