∀ {C : Type u₁} [inst : CategoryTheory.Category.{u₂, u₁} C] [inst_1 : CategoryTheory.GaloisCategory C]
  (F : CategoryTheory.Functor C FintypeCat) [CategoryTheory.PreGaloisCategory.FiberFunctor F] (A : C)
  [CategoryTheory.PreGaloisCategory.IsGalois A] (a : (F.obj A).obj),
  Function.Bijective fun f => (CategoryTheory.ConcreteCategory.hom (F.map f.hom)) a