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Mathlib.CategoryTheory.Sites.PreservesLocallyBijective

Preserving and reflecting local injectivity and surjectivity #

This file proves that precomposition with a cocontinuous functor preserves local injectivity and surjectivity of morphisms of presheaves, and that precomposition with a cover preserving and cover dense functor reflects the same properties.

theorem CategoryTheory.Presheaf.isLocallyInjective_whisker {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] [H.IsCocontinuous J K] [IsLocallyInjective K f] :
theorem CategoryTheory.Presheaf.isLocallyInjective_of_whisker {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] (hH : CoverPreserving J K H) [H.IsCoverDense K] [IsLocallyInjective J (whiskerLeft H.op f)] :
theorem CategoryTheory.Presheaf.isLocallyInjective_whisker_iff {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] (hH : CoverPreserving J K H) [H.IsCocontinuous J K] [H.IsCoverDense K] :
theorem CategoryTheory.Presheaf.isLocallySurjective_whisker {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] [H.IsCocontinuous J K] [IsLocallySurjective K f] :
theorem CategoryTheory.Presheaf.isLocallySurjective_of_whisker {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] (hH : CoverPreserving J K H) [H.IsCoverDense K] [IsLocallySurjective J (whiskerLeft H.op f)] :
theorem CategoryTheory.Presheaf.isLocallySurjective_whisker_iff {C : Type u_1} {D : Type u_2} {A : Type u_3} [Category.{u_6, u_1} C] [Category.{u_7, u_2} D] [Category.{u_8, u_3} A] (J : GrothendieckTopology C) (K : GrothendieckTopology D) (H : Functor C D) {F G : Functor Dᵒᵖ A} (f : F G) {FA : AAType u_4} {CA : AType u_5} [(X Y : A) → FunLike (FA X Y) (CA X) (CA Y)] [ConcreteCategory A FA] (hH : CoverPreserving J K H) [H.IsCocontinuous J K] [H.IsCoverDense K] :