Documentation

Mathlib.CategoryTheory.Sites.LeftExact

Left exactness of sheafification #

In this file we show that sheafification commutes with finite limits.

An auxiliary definition to be used in the proof of the fact that J.diagramFunctor D X preserves limits.

Equations
  • One or more equations did not get rendered due to their size.
Instances For

    Auxiliary definition for liftToDiagramLimitObj.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For
      @[reducible, inline]

      An auxiliary definition to be used in the proof of the fact that J.diagramFunctor D X preserves limits.

      Equations
      • One or more equations did not get rendered due to their size.
      Instances For

        An auxiliary definition to be used in the proof that J.plusFunctor D commutes with finite limits.

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For
          def CategoryTheory.plusPlusSheafIsoPresheafToSheaf {C : Type u} [Category.{v, u} C] (J : GrothendieckTopology C) (D : Type w) [Category.{t, w} D] [∀ (P : Functor Cᵒᵖ D) (X : C) (S : J.Cover X), Limits.HasMultiequalizer (S.index P)] [∀ (X : C), Limits.HasColimitsOfShape (J.Cover X)ᵒᵖ D] {FD : DDType u_1} {CD : DType t} [(X Y : D) → FunLike (FD X Y) (CD X) (CD Y)] [ConcreteCategory D FD] [∀ (X : C), Limits.PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)] [(forget D).ReflectsIsomorphisms] [∀ {X : C} (S : J.Cover X), Limits.PreservesLimitsOfShape (Limits.WalkingMulticospan S.shape) (forget D)] :

          plusPlusSheaf is isomorphic to an arbitrary choice of left adjoint.

          Equations
          Instances For
            def CategoryTheory.plusPlusFunctorIsoSheafification {C : Type u} [Category.{v, u} C] (J : GrothendieckTopology C) (D : Type w) [Category.{t, w} D] [∀ (P : Functor Cᵒᵖ D) (X : C) (S : J.Cover X), Limits.HasMultiequalizer (S.index P)] [∀ (X : C), Limits.HasColimitsOfShape (J.Cover X)ᵒᵖ D] {FD : DDType u_1} {CD : DType t} [(X Y : D) → FunLike (FD X Y) (CD X) (CD Y)] [ConcreteCategory D FD] [∀ (X : C), Limits.PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)] [(forget D).ReflectsIsomorphisms] [∀ {X : C} (S : J.Cover X), Limits.PreservesLimitsOfShape (Limits.WalkingMulticospan S.shape) (forget D)] :

            plusPlusFunctor is isomorphic to sheafification.

            Equations
            Instances For
              def CategoryTheory.plusPlusIsoSheafify {C : Type u} [Category.{v, u} C] (J : GrothendieckTopology C) (D : Type w) [Category.{t, w} D] [∀ (P : Functor Cᵒᵖ D) (X : C) (S : J.Cover X), Limits.HasMultiequalizer (S.index P)] [∀ (X : C), Limits.HasColimitsOfShape (J.Cover X)ᵒᵖ D] {FD : DDType u_1} {CD : DType t} [(X Y : D) → FunLike (FD X Y) (CD X) (CD Y)] [ConcreteCategory D FD] [∀ (X : C), Limits.PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)] [(forget D).ReflectsIsomorphisms] [∀ {X : C} (S : J.Cover X), Limits.PreservesLimitsOfShape (Limits.WalkingMulticospan S.shape) (forget D)] (P : Functor Cᵒᵖ D) :

              plusPlus is isomorphic to sheafify.

              Equations
              Instances For
                @[simp]
                theorem CategoryTheory.toSheafify_plusPlusIsoSheafify_hom {C : Type u} [Category.{v, u} C] (J : GrothendieckTopology C) (D : Type w) [Category.{t, w} D] [∀ (P : Functor Cᵒᵖ D) (X : C) (S : J.Cover X), Limits.HasMultiequalizer (S.index P)] [∀ (X : C), Limits.HasColimitsOfShape (J.Cover X)ᵒᵖ D] {FD : DDType u_1} {CD : DType t} [(X Y : D) → FunLike (FD X Y) (CD X) (CD Y)] [ConcreteCategory D FD] [∀ (X : C), Limits.PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)] [(forget D).ReflectsIsomorphisms] [∀ {X : C} (S : J.Cover X), Limits.PreservesLimitsOfShape (Limits.WalkingMulticospan S.shape) (forget D)] (P : Functor Cᵒᵖ D) :
                @[simp]
                theorem CategoryTheory.toSheafify_plusPlusIsoSheafify_hom_assoc {C : Type u} [Category.{v, u} C] (J : GrothendieckTopology C) (D : Type w) [Category.{t, w} D] [∀ (P : Functor Cᵒᵖ D) (X : C) (S : J.Cover X), Limits.HasMultiequalizer (S.index P)] [∀ (X : C), Limits.HasColimitsOfShape (J.Cover X)ᵒᵖ D] {FD : DDType u_1} {CD : DType t} [(X Y : D) → FunLike (FD X Y) (CD X) (CD Y)] [ConcreteCategory D FD] [∀ (X : C), Limits.PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)] [(forget D).ReflectsIsomorphisms] [∀ {X : C} (S : J.Cover X), Limits.PreservesLimitsOfShape (Limits.WalkingMulticospan S.shape) (forget D)] (P : Functor Cᵒᵖ D) {Z : Functor Cᵒᵖ D} (h : sheafify J P Z) :