Module

FiniteH1PullbackIdentity.lean

Nyll.EtaleFundamentalGroups.Cohomology.FiniteH1PullbackIdentity
2 declarations indexed from sourceView source ↗

Identity and isomorphism pullback on actual finite H¹

Declarations

EtaleFundamentalGroups.Cohomology.constantFiniteH1Pullback_injective_of_fundamentalGroupHom_surjective

Surjectivity on actual fundamental groups implies injectivity of the already constructed derived H¹ pullback.

Source context 3 commands

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

noncomputable section
open CategoryTheory AlgebraicGeometry
namespace EtaleFundamentalGroups.Cohomology
theorem constantFiniteH1Pullback_injective_of_fundamentalGroupHom_surjective
    {X Y : Scheme} [ConnectedSpace X] [ConnectedSpace Y]
    (f : X ⟶ Y) {Ω : Type} [Field Ω] [IsSepClosed Ω]
    (geom : Spec (.of Ω) ⟶ X) (A : AddCommGrpCat.{0}) [Finite A]
    (hf : Function.Surjective (FiniteEtale.fundamentalGroupHom f geom)) :
    Function.Injective (constantCohomologyPullback f A 1)
EtaleFundamentalGroups.Cohomology.constantFiniteH1Pullback_id

Pullback by the identity acts as the identity on actual derived finite H¹.

Source context 3 commands

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

noncomputable section
open CategoryTheory AlgebraicGeometry
namespace EtaleFundamentalGroups.Cohomology
theorem constantFiniteH1Pullback_id
    {X : Scheme} [ConnectedSpace X]
    {Ω : Type} [Field Ω] [IsSepClosed Ω]
    (geom : Spec (.of Ω) ⟶ X) (A : AddCommGrpCat.{0}) [Finite A]
    (c : Sheaf.H.{0} ((constantSheaf X.smallEtaleTopology AddCommGrpCat.{0}).obj A) 1) :
    constantCohomologyPullback (𝟙 X) A 1 c = c