Documentation

Mathlib.Algebra.Homology.ShortComplex.Basic

Short complexes #

This file defines the category ShortComplex C of diagrams X₁X₂X₃ such that the composition is zero.

TODO: A homology API for these objects shall be developed in the folder Algebra.Homology.ShortComplex and eventually the homology of objects in HomologicalComplex C c shall be redefined using this.

Note: This structure ShortComplex C was first introduced in the Liquid Tensor Experiment.

A short complex in a category C with zero morphisms is the datum of two composable morphisms f : X₁X₂ and g : X₂X₃ such that fg = 0.

Instances For
    theorem CategoryTheory.ShortComplex.Hom.ext {C : Type u_1} :
    ∀ {inst : CategoryTheory.Category.{u_3, u_1} C} {inst_1 : CategoryTheory.Limits.HasZeroMorphisms C} {S₁ S₂ : CategoryTheory.ShortComplex C} (x y : CategoryTheory.ShortComplex.Hom S₁ S₂), x.τ₁ = y.τ₁x.τ₂ = y.τ₂x.τ₃ = y.τ₃x = y
    theorem CategoryTheory.ShortComplex.Hom.ext_iff {C : Type u_1} :
    ∀ {inst : CategoryTheory.Category.{u_3, u_1} C} {inst_1 : CategoryTheory.Limits.HasZeroMorphisms C} {S₁ S₂ : CategoryTheory.ShortComplex C} (x y : CategoryTheory.ShortComplex.Hom S₁ S₂), x = y x.τ₁ = y.τ₁ x.τ₂ = y.τ₂ x.τ₃ = y.τ₃

    Morphisms of short complexes are the commutative diagrams of the obvious shape.

    Instances For

      The identity morphism of a short complex.

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

        The composition of morphisms of short complexes.

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For
          theorem CategoryTheory.ShortComplex.hom_ext {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (f : S₁ S₂) (g : S₁ S₂) (h₁ : f.τ₁ = g.τ₁) (h₂ : f.τ₂ = g.τ₂) (h₃ : f.τ₃ = g.τ₃) :
          f = g
          @[simp]
          theorem CategoryTheory.ShortComplex.homMk_τ₂ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (τ₁ : S₁.X₁ S₂.X₁) (τ₂ : S₁.X₂ S₂.X₂) (τ₃ : S₁.X₃ S₂.X₃) (comm₁₂ : CategoryTheory.CategoryStruct.comp τ₁ S₂.f = CategoryTheory.CategoryStruct.comp S₁.f τ₂) (comm₂₃ : CategoryTheory.CategoryStruct.comp τ₂ S₂.g = CategoryTheory.CategoryStruct.comp S₁.g τ₃) :
          (CategoryTheory.ShortComplex.homMk τ₁ τ₂ τ₃ comm₁₂ comm₂₃).τ₂ = τ₂
          @[simp]
          theorem CategoryTheory.ShortComplex.homMk_τ₁ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (τ₁ : S₁.X₁ S₂.X₁) (τ₂ : S₁.X₂ S₂.X₂) (τ₃ : S₁.X₃ S₂.X₃) (comm₁₂ : CategoryTheory.CategoryStruct.comp τ₁ S₂.f = CategoryTheory.CategoryStruct.comp S₁.f τ₂) (comm₂₃ : CategoryTheory.CategoryStruct.comp τ₂ S₂.g = CategoryTheory.CategoryStruct.comp S₁.g τ₃) :
          (CategoryTheory.ShortComplex.homMk τ₁ τ₂ τ₃ comm₁₂ comm₂₃).τ₁ = τ₁
          @[simp]
          theorem CategoryTheory.ShortComplex.homMk_τ₃ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (τ₁ : S₁.X₁ S₂.X₁) (τ₂ : S₁.X₂ S₂.X₂) (τ₃ : S₁.X₃ S₂.X₃) (comm₁₂ : CategoryTheory.CategoryStruct.comp τ₁ S₂.f = CategoryTheory.CategoryStruct.comp S₁.f τ₂) (comm₂₃ : CategoryTheory.CategoryStruct.comp τ₂ S₂.g = CategoryTheory.CategoryStruct.comp S₁.g τ₃) :
          (CategoryTheory.ShortComplex.homMk τ₁ τ₂ τ₃ comm₁₂ comm₂₃).τ₃ = τ₃
          def CategoryTheory.ShortComplex.homMk {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (τ₁ : S₁.X₁ S₂.X₁) (τ₂ : S₁.X₂ S₂.X₂) (τ₃ : S₁.X₃ S₂.X₃) (comm₁₂ : CategoryTheory.CategoryStruct.comp τ₁ S₂.f = CategoryTheory.CategoryStruct.comp S₁.f τ₂) (comm₂₃ : CategoryTheory.CategoryStruct.comp τ₂ S₂.g = CategoryTheory.CategoryStruct.comp S₁.g τ₃) :
          S₁ S₂

          A constructor for morphisms in ShortComplex C when the commutativity conditions are not obvious.

          Equations
          • CategoryTheory.ShortComplex.homMk τ₁ τ₂ τ₃ comm₁₂ comm₂₃ = { τ₁ := τ₁, τ₂ := τ₂, τ₃ := τ₃, comm₁₂ := comm₁₂, comm₂₃ := comm₂₃ }
          Instances For
            Equations
            • CategoryTheory.ShortComplex.instZeroHomShortComplexToQuiverToCategoryStructInstCategoryShortComplex = { zero := { τ₁ := 0, τ₂ := 0, τ₃ := 0, comm₁₂ := , comm₂₃ := } }
            @[simp]
            theorem CategoryTheory.ShortComplex.π₁_map {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
            ∀ {X Y : CategoryTheory.ShortComplex C} (f : X Y), CategoryTheory.ShortComplex.π₁.map f = f.τ₁

            The first projection functor ShortComplex C ⥤ C.

            Equations
            • One or more equations did not get rendered due to their size.
            Instances For
              @[simp]
              theorem CategoryTheory.ShortComplex.π₂_map {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
              ∀ {X Y : CategoryTheory.ShortComplex C} (f : X Y), CategoryTheory.ShortComplex.π₂.map f = f.τ₂

              The second projection functor ShortComplex C ⥤ C.

              Equations
              • One or more equations did not get rendered due to their size.
              Instances For
                @[simp]
                theorem CategoryTheory.ShortComplex.π₃_map {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
                ∀ {X Y : CategoryTheory.ShortComplex C} (f : X Y), CategoryTheory.ShortComplex.π₃.map f = f.τ₃

                The third projection functor ShortComplex C ⥤ C.

                Equations
                • One or more equations did not get rendered due to their size.
                Instances For
                  def CategoryTheory.ShortComplex.π₁Toπ₂ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
                  CategoryTheory.ShortComplex.π₁ CategoryTheory.ShortComplex.π₂

                  The natural transformation π₁π₂ induced by S.f for all S : ShortComplex C.

                  Equations
                  Instances For
                    def CategoryTheory.ShortComplex.π₂Toπ₃ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
                    CategoryTheory.ShortComplex.π₂ CategoryTheory.ShortComplex.π₃

                    The natural transformation π₂π₃ induced by S.g for all S : ShortComplex C.

                    Equations
                    Instances For
                      @[simp]
                      theorem CategoryTheory.ShortComplex.π₁Toπ₂_comp_π₂Toπ₃ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] :
                      CategoryTheory.CategoryStruct.comp CategoryTheory.ShortComplex.π₁Toπ₂ CategoryTheory.ShortComplex.π₂Toπ₃ = 0

                      The short complex in D obtained by applying a functor F : C ⥤ D to a short complex in C, assuming that F preserves zero morphisms.

                      Equations
                      Instances For

                        The morphism of short complexes S.map F ⟶ S.map G induced by a natural transformation F ⟶ G.

                        Equations
                        Instances For
                          @[simp]
                          theorem CategoryTheory.ShortComplex.isoMk_hom_τ₂ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (e₁ : S₁.X₁ S₂.X₁) (e₂ : S₁.X₂ S₂.X₂) (e₃ : S₁.X₃ S₂.X₃) (comm₁₂ : autoParam (CategoryTheory.CategoryStruct.comp e₁.hom S₂.f = CategoryTheory.CategoryStruct.comp S₁.f e₂.hom) _auto✝) (comm₂₃ : autoParam (CategoryTheory.CategoryStruct.comp e₂.hom S₂.g = CategoryTheory.CategoryStruct.comp S₁.g e₃.hom) _auto✝) :
                          (CategoryTheory.ShortComplex.isoMk e₁ e₂ e₃ comm₁₂ comm₂₃).hom.τ₂ = e₂.hom
                          @[simp]
                          theorem CategoryTheory.ShortComplex.isoMk_hom_τ₃ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (e₁ : S₁.X₁ S₂.X₁) (e₂ : S₁.X₂ S₂.X₂) (e₃ : S₁.X₃ S₂.X₃) (comm₁₂ : autoParam (CategoryTheory.CategoryStruct.comp e₁.hom S₂.f = CategoryTheory.CategoryStruct.comp S₁.f e₂.hom) _auto✝) (comm₂₃ : autoParam (CategoryTheory.CategoryStruct.comp e₂.hom S₂.g = CategoryTheory.CategoryStruct.comp S₁.g e₃.hom) _auto✝) :
                          (CategoryTheory.ShortComplex.isoMk e₁ e₂ e₃ comm₁₂ comm₂₃).hom.τ₃ = e₃.hom
                          @[simp]
                          theorem CategoryTheory.ShortComplex.isoMk_hom_τ₁ {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (e₁ : S₁.X₁ S₂.X₁) (e₂ : S₁.X₂ S₂.X₂) (e₃ : S₁.X₃ S₂.X₃) (comm₁₂ : autoParam (CategoryTheory.CategoryStruct.comp e₁.hom S₂.f = CategoryTheory.CategoryStruct.comp S₁.f e₂.hom) _auto✝) (comm₂₃ : autoParam (CategoryTheory.CategoryStruct.comp e₂.hom S₂.g = CategoryTheory.CategoryStruct.comp S₁.g e₃.hom) _auto✝) :
                          (CategoryTheory.ShortComplex.isoMk e₁ e₂ e₃ comm₁₂ comm₂₃).hom.τ₁ = e₁.hom
                          @[simp]
                          theorem CategoryTheory.ShortComplex.isoMk_inv {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (e₁ : S₁.X₁ S₂.X₁) (e₂ : S₁.X₂ S₂.X₂) (e₃ : S₁.X₃ S₂.X₃) (comm₁₂ : autoParam (CategoryTheory.CategoryStruct.comp e₁.hom S₂.f = CategoryTheory.CategoryStruct.comp S₁.f e₂.hom) _auto✝) (comm₂₃ : autoParam (CategoryTheory.CategoryStruct.comp e₂.hom S₂.g = CategoryTheory.CategoryStruct.comp S₁.g e₃.hom) _auto✝) :
                          (CategoryTheory.ShortComplex.isoMk e₁ e₂ e₃ comm₁₂ comm₂₃).inv = CategoryTheory.ShortComplex.homMk e₁.inv e₂.inv e₃.inv
                          def CategoryTheory.ShortComplex.isoMk {C : Type u_1} [CategoryTheory.Category.{u_3, u_1} C] [CategoryTheory.Limits.HasZeroMorphisms C] {S₁ : CategoryTheory.ShortComplex C} {S₂ : CategoryTheory.ShortComplex C} (e₁ : S₁.X₁ S₂.X₁) (e₂ : S₁.X₂ S₂.X₂) (e₃ : S₁.X₃ S₂.X₃) (comm₁₂ : autoParam (CategoryTheory.CategoryStruct.comp e₁.hom S₂.f = CategoryTheory.CategoryStruct.comp S₁.f e₂.hom) _auto✝) (comm₂₃ : autoParam (CategoryTheory.CategoryStruct.comp e₂.hom S₂.g = CategoryTheory.CategoryStruct.comp S₁.g e₃.hom) _auto✝) :
                          S₁ S₂

                          A constructor for isomorphisms in the category ShortComplex C

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

                            The opposite morphism in ShortComplex Cᵒᵖ associated to a morphism in ShortComplex C

                            Equations
                            Instances For

                              The morphism in ShortComplex C associated to a morphism in ShortComplex Cᵒᵖ

                              Equations
                              Instances For

                                The obvious functor (ShortComplex C)ᵒᵖ ⥤ ShortComplex Cᵒᵖ.

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

                                  The obvious functor ShortComplex Cᵒᵖ ⥤ (ShortComplex C)ᵒᵖ.

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

                                    The obvious equivalence of categories (ShortComplex C)ᵒᵖ ≌ ShortComplex Cᵒᵖ.

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