import Mathlib open CategoryTheory variable {C D E : Type*} [Category C] [Category D] [Category E] namespace CategoryTheory class Functor.ReflectsSplitEpimorphismsToRegularEpimorphisms (F : Functor C D) : Prop where reflects : ∀ {X Y} {f : X ⟶ Y} [IsSplitEpi (F.map f)], Nonempty (RegularEpi f) end CategoryTheory variable (U : D ⥤ C) (V : E ⥤ C) (F : D ⥤ E) theorem exists_left_adjoint_of_comp_eq (h : F ⋙ V = U) (hU : U.IsRightAdjoint) (hV : V.IsRightAdjoint) (hV_refl : V.ReflectsSplitEpimorphismsToRegularEpimorphisms) : F.IsRightAdjoint := by sorry