∀ {V : Type u_1} {P : Type u_2} {α : Type u_3} [inst : AddGroup V] [inst_1 : TopologicalSpace V]
  [inst_2 : AddTorsor V P] [inst_3 : TopologicalSpace P] [IsTopologicalAddTorsor P] [inst_5 : TopologicalSpace α]
  {f g : α → P} {s : Set α}, ContinuousOn f s → ContinuousOn g s → ContinuousOn (fun x => f x -ᵥ g x) s