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Mathlib.Algebra.Category.ModuleCat.Presheaf.EpiMono

Epimorphisms and monomorphisms in the category of presheaves of modules #

In this file, we give characterizations of epimorphisms and monomorphisms in the category of presheaves of modules.

theorem PresheafOfModules.epi_of_surjective {C : Type u₁} [CategoryTheory.Category.{v₁, u₁} C] {R : CategoryTheory.Functor Cįµ’įµ– RingCat} {M₁ Mā‚‚ : PresheafOfModules R} {f : M₁ ⟶ Mā‚‚} (hf : āˆ€ ⦃X : Cᵒᵖ⦄, Function.Surjective ⇑(CategoryTheory.ConcreteCategory.hom (f.app X))) :
theorem PresheafOfModules.mono_of_injective {C : Type u₁} [CategoryTheory.Category.{v₁, u₁} C] {R : CategoryTheory.Functor Cįµ’įµ– RingCat} {M₁ Mā‚‚ : PresheafOfModules R} {f : M₁ ⟶ Mā‚‚} (hf : āˆ€ ⦃X : Cᵒᵖ⦄, Function.Injective ⇑(CategoryTheory.ConcreteCategory.hom (f.app X))) :
theorem PresheafOfModules.epi_iff_surjective {C : Type u₁} [CategoryTheory.Category.{v₁, u₁} C] {R : CategoryTheory.Functor Cįµ’įµ– RingCat} {M₁ Mā‚‚ : PresheafOfModules R} (f : M₁ ⟶ Mā‚‚) :
CategoryTheory.Epi f ↔ āˆ€ ⦃X : Cᵒᵖ⦄, Function.Surjective ⇑(CategoryTheory.ConcreteCategory.hom (f.app X))