Multiplicative bases

MultiplicativeBasisDeformations.Foundations.A0RepFinite

Proposition 2.10(2): A₀ is representation-finite #

prop:projective-evaluation(2) (graded-category.tex): evaluation add C → mod A₀ is an equivalence, so the indecomposable A₀-modules are the evaluations of the finitely many objects of C.

Every finite-dimensional module is the evaluation of a family (InjData.essSurj); an indecomposable one has local endomorphism ring and is a retract of one summand (exchange), which is an evaluation R_x with local endomorphism ring C(x, x) (full faithfulness), hence isomorphic to it. Modules of Alg F₀ are the paper's right A₀-modules; they are transported to right modules of (Alg F₀)ᵒᵖ along R ≅ Rᵒᵖᵒᵖ.

Left modules versus right modules of the opposite algebra #

noncomputable def MultiplicativeBasisDeformations.toOpOp {A : Type v} [Ring A] :
ModuleCat A ≌ RightModuleCat Aᵐᵒᵖ

Left A-modules as right Aᵒᵖ-modules.

Instances For
    def MultiplicativeBasisDeformations.toOpOpK {k : Type u} [Field k] {A : Type v} [Ring A] [Algebra k A] (M : ModuleCat A) :
    ↑M →ₗ[k] ↑(toOpOp.functor.obj M)

    The identity map is k-linear for the induced structures.

    Instances For
      def MultiplicativeBasisDeformations.ofOpOpK {k : Type u} [Field k] {A : Type v} [Ring A] [Algebra k A] (N : RightModuleCat Aᵐᵒᵖ) :
      ↑N →ₗ[k] ↑(toOpOp.inverse.obj N)

      And back.

      Instances For
        theorem MultiplicativeBasisDeformations.isRepresentationFinite_op_of_left {k : Type u} [Field k] {A : Type v} [Ring A] [Algebra k A] [FiniteDimensional k A] {n : ℕ} (X : Fin n → ModuleCat A) (hX : ∀ (i : Fin n), Module.Finite k ↑(X i) ∧ IsLocalRing (CategoryTheory.End (X i))) (hcov : ∀ (M : ModuleCat A), Module.Finite k ↑M → CategoryTheory.Indecomposable M → ∃ (i : Fin n), Nonempty (M ≅ X i)) :

        Representation-finiteness of Aᵒᵖ from a finite list of left A-modules.

        theorem MultiplicativeBasisDeformations.CatAlg.LocalFamily.end_isLocalRing {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} (L : LocalFamily F) (x : ι) :
        IsLocalRing (CategoryTheory.End (F x))

        Endomorphism rings in a local family are local.

        instance MultiplicativeBasisDeformations.CatAlg.MeshData.instFiniteDimensionalAlgPVF0 {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] :
        FiniteDimensional k (Alg D.F0)
        instance MultiplicativeBasisDeformations.CatAlg.MeshData.instFiniteDimensionalRepPVF0 {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (x : ι) :
        FiniteDimensional k (Rep D.F0 (F x))
        def MultiplicativeBasisDeformations.CatAlg.MeshData.evObj {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} (x : ι) :
        ModuleCat (Alg D.F0)

        The evaluation R⁰_x of a label as a module.

        Instances For
          def MultiplicativeBasisDeformations.CatAlg.MeshData.evObjK {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} (x : ι) :
          Rep D.F0 (F x) →ₗ[k] ↑(evObj x)

          The identity of R⁰_x from the native k-structure.

          Instances For
            instance MultiplicativeBasisDeformations.CatAlg.MeshData.evObj_finite {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (x : ι) :
            Module.Finite k ↑(evObj x)
            def MultiplicativeBasisDeformations.CatAlg.MeshData.evHom {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} {x : ι} (f : F x ⟶ F x) :
            evObj x ⟶ evObj x

            The evaluation of an endomorphism.

            Instances For
              theorem MultiplicativeBasisDeformations.CatAlg.MeshData.evHom_apply {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] {x : ι} (f : F x ⟶ F x) (m : Rep D.F0 (F x)) :
              (ModuleCat.Hom.hom (evHom f)) m = (repMap f) m
              def MultiplicativeBasisDeformations.CatAlg.MeshData.evEndHom {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} (x : ι) :
              CategoryTheory.End (F x) →+* CategoryTheory.End (evObj x)

              Endomorphisms of an evaluation are evaluations of endomorphisms.

              Instances For
                theorem MultiplicativeBasisDeformations.CatAlg.MeshData.evEndHom_bijective {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (x : ι) :
                Function.Bijective ⇑(evEndHom x)
                theorem MultiplicativeBasisDeformations.CatAlg.MeshData.evObj_isLocalRing {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (x : ι) :
                IsLocalRing (CategoryTheory.End (evObj x))
                theorem MultiplicativeBasisDeformations.CatAlg.MeshData.exists_iso_evObj {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (J : D.InjData) (M : ModuleCat (Alg D.F0)) [Module.Finite k ↑M] (hM : CategoryTheory.Indecomposable M) :
                ∃ (x : ι), Nonempty (M ≅ evObj x)

                Every finite-dimensional indecomposable A₀-module is the evaluation of a label.

                theorem MultiplicativeBasisDeformations.CatAlg.MeshData.isRepresentationFinite_A0 {k : Type u} [Field k] {𝒞 : Type v} [CategoryTheory.Category.{w, v} 𝒞] [CategoryTheory.Preadditive 𝒞] [CategoryTheory.Linear k 𝒞] {ι : Type} [Fintype ι] [DecidableEq ι] {F : ι → 𝒞} {L : LocalFamily F} {D : MeshData F L} [hfd : ∀ (x y : ι), FiniteDimensional k (F x ⟶ F y)] (J : D.InjData) :

                Proposition 2.10(2): A₀ is representation-finite.