∀ {F : Type u_1} [inst : NormedAddCommGroup F] [inst_1 : NormedSpace ℝ F] (f : ℝ → F) {K : Set F},
  IsComplete K → MeasurableSet {x | DifferentiableWithinAt ℝ f (Set.Ici x) x ∧ derivWithin f (Set.Ici x) x ∈ K}