Documentation

TauCeti.Algebra.Homology.Curved.Module.Right.Cone.Basic

Mapping cones of curved differential graded right modules #

The cone of a closed map f : M ⟶ N has underlying graded right module M[1] × N and differential (x, y) ↦ (-dM x, f x + dN y). The two off-diagonal terms in its square cancel because f commutes with the differentials. Its curvature is therefore the same as the curvature of M and N, without a centrality assumption.

The right action is unchanged. The canonical inclusion of N and projection to M[1] are closed maps, and the adjacent composites vanish in the existing homotopy category. A closed map g : N ⟶ P with f ≫ g = 0 induces the closed map coneDesc f g hfg : cone(f) ⟶ P. A null-homotopic closed map factors through its source's identity cone via the inclusion.

References #

The cone differential uses the linear mapping-cone construction on the ground-ring maps.

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    @[simp]

    The cone differential has diagonal entries -dM and dN and lower-left entry f.

    @[implicit_reducible]

    The cone of a closed map, with grading M[1] × N and the original curvature.

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      @[simp]

      The degree-p part of the cone is Mᵖ⁺¹ × Nᵖ.

      @[simp]

      The differential on the cone acts by the usual block formula.

      The closed projection from the cone to the cohomological shift of its domain.

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        @[simp]

        The inclusion followed by the projection vanishes already in the closed category.

        The first linear inclusion, viewed as a degree-minus-one homotopy into the cone.

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          @[simp]

          The homotopy for the first adjacent composite sends x to (x, 0).

          The first adjacent composite is the boundary of the first inclusion homotopy.

          The second projection, viewed as a degree-minus-one homotopy to the shifted codomain.

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            @[simp]

            The homotopy for the third adjacent composite sends (x, y) to y.

            The contracting homotopy of the cone of an isomorphism applies its inverse to the second component and includes the result into the first component.

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              @[simp]

              The contraction sends (x, y) to (f⁻¹ y, 0).

              A corrected degree-minus-one cochain for a closed map g and cochains α, β. For t = f ∘ α - β ∘ f, its matrix is (α - g ∘ t, g; β ∘ t, -β). It is a contraction when the inverse-homotopy equations in coneHomotopyContraction_boundary hold.

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                @[simp]

                The corrected degree-minus-one cochain has this block formula on the cone carrier.

                Inverse homotopies make the corrected contraction a boundary of the identity. The correction uses the closed odd map t = f ∘ α - β ∘ f, so no coherence between the chosen inverse homotopies, or zero-curvature hypothesis, is required.

                A closed map which becomes an isomorphism in the homotopy category has a contractible cone.

                @[simp]

                The strict inverse contraction is the zero-homotopy case of the corrected contraction.

                The strict contraction boundary follows from the general inverse-homotopy formula.

                @[simp]
                theorem TauCeti.CurvedDGRightModuleCat.coneInclusion_comp_coneMap_assoc {R A : Type u} [CommRing R] [Ring A] [Algebra R A] {𝒜 : ℤ → Submodule R A} [GradedAlgebra 𝒜] {d : A →ₗ[R] A} {w : A} {h : IsCurvedDGAlgebra 𝒜 d w} {M N : CurvedDGRightModuleCat h} (f : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N) {M' N' : CurvedDGRightModuleCat h} (g : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (a : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M') (b : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (k : ↥(dgRightModuleCochains (-1))) (hsq : ∀ (x : M.carrier), (closedHom b) ((closedHom f) x) - (closedHom g) ((closedHom a) x) = N'.differential (↑k x) + ↑k (M.differential x)) {Z : CategoryTheory.ForgetEnrichment (CochainComplex (ModuleCat R) ℤ) (CurvedDGRightModuleCat h)} (h✝ : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) (cone g) ⟶ Z) :

                Cone maps commute with the canonical inclusions.

                @[simp]
                theorem TauCeti.CurvedDGRightModuleCat.coneMap_comp_coneProjection_assoc {R A : Type u} [CommRing R] [Ring A] [Algebra R A] {𝒜 : ℤ → Submodule R A} [GradedAlgebra 𝒜] {d : A →ₗ[R] A} {w : A} {h : IsCurvedDGAlgebra 𝒜 d w} {M N : CurvedDGRightModuleCat h} (f : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N) {M' N' : CurvedDGRightModuleCat h} (g : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (a : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M') (b : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (k : ↥(dgRightModuleCochains (-1))) (hsq : ∀ (x : M.carrier), (closedHom b) ((closedHom f) x) - (closedHom g) ((closedHom a) x) = N'.differential (↑k x) + ↑k (M.differential x)) {Z : CategoryTheory.ForgetEnrichment (CochainComplex (ModuleCat R) ℤ) (CurvedDGRightModuleCat h)} (h✝ : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) (M'.shift 1) ⟶ Z) :

                Cone maps commute with the canonical projections and the shifted domain map.

                The homotopy for a composite of two cone-map squares is b' ∘ k + k' ∘ a.

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                  @[simp]

                  The composite square homotopy evaluates by post- and precomposition.

                  theorem TauCeti.CurvedDGRightModuleCat.coneMapCompHomotopy_boundary {R A : Type u} [CommRing R] [Ring A] [Algebra R A] {𝒜 : ℤ → Submodule R A} [GradedAlgebra 𝒜] {d : A →ₗ[R] A} {w : A} {h : IsCurvedDGAlgebra 𝒜 d w} {M N : CurvedDGRightModuleCat h} (f : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N) {M' N' : CurvedDGRightModuleCat h} (g : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (a : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M') (b : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (k : ↥(dgRightModuleCochains (-1))) (hsq : ∀ (x : M.carrier), (closedHom b) ((closedHom f) x) - (closedHom g) ((closedHom a) x) = N'.differential (↑k x) + ↑k (M.differential x)) {M'' N'' : CurvedDGRightModuleCat h} (j : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (a' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'') (b' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (k' : ↥(dgRightModuleCochains (-1))) (hsq' : ∀ (x : M'.carrier), (closedHom b') ((closedHom g) x) - (closedHom j) ((closedHom a') x) = N''.differential (↑k' x) + ↑k' (M'.differential x)) (x : M.carrier) :

                  The sum of the two square homotopies witnesses the composite square.

                  @[simp]
                  theorem TauCeti.CurvedDGRightModuleCat.coneMap_comp {R A : Type u} [CommRing R] [Ring A] [Algebra R A] {𝒜 : ℤ → Submodule R A} [GradedAlgebra 𝒜] {d : A →ₗ[R] A} {w : A} {h : IsCurvedDGAlgebra 𝒜 d w} {M N : CurvedDGRightModuleCat h} (f : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N) {M' N' : CurvedDGRightModuleCat h} (g : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (a : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M') (b : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (k : ↥(dgRightModuleCochains (-1))) (hsq : ∀ (x : M.carrier), (closedHom b) ((closedHom f) x) - (closedHom g) ((closedHom a) x) = N'.differential (↑k x) + ↑k (M.differential x)) {M'' N'' : CurvedDGRightModuleCat h} (j : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (a' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'') (b' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (k' : ↥(dgRightModuleCochains (-1))) (hsq' : ∀ (x : M'.carrier), (closedHom b') ((closedHom g) x) - (closedHom j) ((closedHom a') x) = N''.differential (↑k' x) + ↑k' (M'.differential x)) :

                  Cone maps compose using the induced composite square homotopy.

                  @[simp]
                  theorem TauCeti.CurvedDGRightModuleCat.coneMap_comp_assoc {R A : Type u} [CommRing R] [Ring A] [Algebra R A] {𝒜 : ℤ → Submodule R A} [GradedAlgebra 𝒜] {d : A →ₗ[R] A} {w : A} {h : IsCurvedDGAlgebra 𝒜 d w} {M N : CurvedDGRightModuleCat h} (f : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N) {M' N' : CurvedDGRightModuleCat h} (g : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (a : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M') (b : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N') (k : ↥(dgRightModuleCochains (-1))) (hsq : ∀ (x : M.carrier), (closedHom b) ((closedHom f) x) - (closedHom g) ((closedHom a) x) = N'.differential (↑k x) + ↑k (M.differential x)) {M'' N'' : CurvedDGRightModuleCat h} (j : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (a' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) M'') (b' : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N' ⟶ CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) N'') (k' : ↥(dgRightModuleCochains (-1))) (hsq' : ∀ (x : M'.carrier), (closedHom b') ((closedHom g) x) - (closedHom j) ((closedHom a') x) = N''.differential (↑k' x) + ↑k' (M'.differential x)) {Z : CategoryTheory.ForgetEnrichment (CochainComplex (ModuleCat R) ℤ) (CurvedDGRightModuleCat h)} (h✝ : CategoryTheory.ForgetEnrichment.of (CochainComplex (ModuleCat R) ℤ) (cone j) ⟶ Z) :

                  Cone maps compose using the induced composite square homotopy.