Module

PrincipalLocalizationTensorCoefficients.lean

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

Tensor coefficients for the principal localization complex

The usual tensor description of module localization identifies tensoring the ring's principal localization complex with the principal complex of the coefficient module. Compatibility with the differential is checked on pure tensors using the actual localization maps.

Imports6
Imported by3

Declarations

EtaleFundamentalGroups.Purity.tensorLocalizedRingEquiv
Source context 6 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u
open CategoryTheory Limits MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def tensorLocalizedRingEquiv (S : Submonoid R) (M : ModuleCat.{u} R) :
    M ⊗[R] LocalizedModule S R ≃ₗ[R] LocalizedModule S M
EtaleFundamentalGroups.Purity.tensorLocalizedRingEquiv_mk
Source context 6 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u
open CategoryTheory Limits MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
theorem tensorLocalizedRingEquiv_mk (S : Submonoid R)
    (M : ModuleCat.{u} R) (m : M) (r : R) :
    tensorLocalizedRingEquiv S M
      (m ⊗ₜ[R] LocalizedModule.mkLinearMap S R r) =
        LocalizedModule.mkLinearMap S M (r • m)
EtaleFundamentalGroups.Purity.principalTensorCoefficientXIso
Source context 6 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u
open CategoryTheory Limits MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def principalTensorCoefficientXIso (x : R) (M : ModuleCat.{u} R) :
    ∀ n : ℕ,
      (((tensorLeft M).mapHomologicalComplex (ComplexShape.up ℕ)).obj
        (principalLocalizationComplex x (ModuleCat.of R R))).X n ≅
          (principalLocalizationComplex x M).X n
  | 0 => ρ_ M
  | 1 => (tensorLocalizedRingEquiv (Submonoid.powers x) M).toModuleIso
  | n + 2 =>
    ((tensorLeft M).map_isZero
      (principalLocalizationComplex_isZero_X x (ModuleCat.of R R) (n + 2) (by omega))).iso
      (principalLocalizationComplex_isZero_X x M (n + 2) (by omega))
EtaleFundamentalGroups.Purity.principalLocalizationTensorCoefficientsIso

Tensoring the principal complex of the ring with a coefficient module gives its actual principal localization complex.

Source context 6 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Purity
universe u
open CategoryTheory Limits MonoidalCategory
open scoped TensorProduct
variable {R : Type u} [CommRing R]
def principalLocalizationTensorCoefficientsIso (x : R) (M : ModuleCat.{u} R) :
    ((tensorLeft M).mapHomologicalComplex (ComplexShape.up ℕ)).obj
      (principalLocalizationComplex x (ModuleCat.of R R)) ≅
        principalLocalizationComplex x M