∀ {X : Type u_1} {Y : Type u_2} {Z : Type u_3} [inst : TopologicalSpace X] [inst_1 : TopologicalSpace Y]
  [inst_2 : TopologicalSpace Z] {f : X → Y} {g : Y → Z}, SpecializingMap f → SpecializingMap g → SpecializingMap (g ∘ f)