Module

TensorLinearDualComplex.lean

Nyll.EtaleFundamentalGroups.Purity.TensorLinearDualComplex
4 declarations indexed from sourceView source ↗

Tensor coefficients and linear-dual complexes

The tensor--Hom correspondence is linear and natural in the variable complex. Consequently applying linear Hom from a coefficient module to the dual complex agrees with dualizing the complex after tensoring with that coefficient module. If the original terms are flat and the dual values are injective, the dual terms are injective.

Declarations

EtaleFundamentalGroups.Purity.tensorLinearDualHomEquiv

The tensor--Hom correspondence with bundled module morphisms, including its linear structure.

Source context 6 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u v
open CategoryTheory Opposite MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def tensorLinearDualHomEquiv (M N E : ModuleCat.{u} R) :
    (M ⟶ ModuleCat.of R (N ⟶ E)) ≃ₗ[R] (M ⊗ N ⟶ E) where
  toFun f := ModuleCat.ofHom (TensorProduct.lift f.hom₂)
  invFun g := ModuleCat.ofHom₂ (TensorProduct.curry g.hom)
  left_inv f := by
    ext m n
    rfl
  right_inv g := by
    ext m n
    rfl
  map_add' f g := by
    ext m n
    rfl
  map_smul' a f := by
    ext m n
    rfl
EtaleFundamentalGroups.Purity.tensorLinearDualHomIso

Naturality of tensor--Hom in the contravariant module argument.

Source context 6 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u v
open CategoryTheory Opposite MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def tensorLinearDualHomIso (M E : ModuleCat.{u} R) :
    (linearYoneda R (ModuleCat.{u} R)).obj E ⋙
        (linearCoyoneda R (ModuleCat.{u} R)).obj (op M) ≅
      (tensorLeft M).op ⋙ (linearYoneda R (ModuleCat.{u} R)).obj E
EtaleFundamentalGroups.Purity.tensorLinearDualComplexIso

Hom from a module into a reversed dual complex is the reversed dual of the complex with tensor coefficients.

Source context 6 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u v
open CategoryTheory Opposite MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def tensorLinearDualComplexIso
    (M E : ModuleCat.{u} R) {ι : Type v} {c : ComplexShape ι}
    (K : HomologicalComplex (ModuleCat.{u} R) c) :
    (((linearCoyoneda R (ModuleCat.{u} R)).obj (op M)).mapHomologicalComplex
        c.symm).obj (linearDualComplex E K) ≅
      linearDualComplex E ((tensorLeft M).mapHomologicalComplex c |>.obj K)
EtaleFundamentalGroups.Purity.injective_linearDualComplex_X

Each term of the injective-valued dual of a flat complex is injective.

Source context 6 commands

Surrounding namespaces, section variables, and local commands at this declaration.

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u v
open CategoryTheory Opposite MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
theorem injective_linearDualComplex_X
    (E : ModuleCat.{u} R) [Module.Injective R E]
    {ι : Type v} {c : ComplexShape ι}
    (K : HomologicalComplex (ModuleCat.{u} R) c) (j : ι)
    [Module.Flat R (K.X j)] :
    Module.Injective R ((linearDualComplex E K).X j)