Module

PadicH1Comparison.lean

Nyll.EtaleFundamentalGroups.Cohomology.PadicH1Comparison
21 declarations indexed from sourceView source ↗

Classical integral ℓ-adic H¹ and p-adic continuous characters

Compatible finite characters determine actual p-adic integers, whose topology is detected by reduction at every level. Consequently their pointwise limit is continuous. Combined with the finite-coefficient étale H¹ comparison this identifies classical integral ℓ-adic H¹ with continuous p-adic characters of the actual étale fundamental group. Connectedness and a geometric point are the only geometric assumptions.

Declarations

EtaleFundamentalGroups.Cohomology.finiteCoefficientTopology
Source context 7 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n))
EtaleFundamentalGroups.Cohomology.finiteCoefficientDiscrete
Source context 8 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n))
EtaleFundamentalGroups.Cohomology.residueTopology
Source context 9 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n))
EtaleFundamentalGroups.Cohomology.residueDiscrete
Source context 10 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n))
EtaleFundamentalGroups.Cohomology.padicCharacters

Continuous characters into the actual additive p-adic integers.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
abbrev padicCharacters : Type (u + 1)
EtaleFundamentalGroups.Cohomology.characterResidues
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def characterResidues (χ : compatibleFiniteCharacters ξ ℓ)
    (g : Aut (FiniteEtale.fiber ξ)) : compatibleResidues ℓ
EtaleFundamentalGroups.Cohomology.characterLimit
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def characterLimit (χ : compatibleFiniteCharacters ξ ℓ)
    (g : Aut (FiniteEtale.fiber ξ)) : ℤ_[ℓ]
EtaleFundamentalGroups.Cohomology.characterLimit_spec
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem characterLimit_spec (χ : compatibleFiniteCharacters ξ ℓ)
    (g : Aut (FiniteEtale.fiber ξ)) (n : ℕ) :
    PadicInt.toZModPow (n + 1) (characterLimit ξ ℓ χ g) =
      ((χ.val n).toMul g).toAdd.down
EtaleFundamentalGroups.Cohomology.padic_ext_positive
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem padic_ext_positive {a b : ℤ_[ℓ]}
    (h : ∀ n, PadicInt.toZModPow (n + 1) a = PadicInt.toZModPow (n + 1) b) : a = b
EtaleFundamentalGroups.Cohomology.characterLimit_mul
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem characterLimit_mul (χ : compatibleFiniteCharacters ξ ℓ)
    (g h : Aut (FiniteEtale.fiber ξ)) :
    characterLimit ξ ℓ χ (g * h) = characterLimit ξ ℓ χ g + characterLimit ξ ℓ χ h
EtaleFundamentalGroups.Cohomology.characterLimit_one
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem characterLimit_one (χ : compatibleFiniteCharacters ξ ℓ) :
    characterLimit ξ ℓ χ 1 = 0
EtaleFundamentalGroups.Cohomology.continuous_characterLimit
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem continuous_characterLimit (χ : compatibleFiniteCharacters ξ ℓ) :
    Continuous (characterLimit ξ ℓ χ)
EtaleFundamentalGroups.Cohomology.compatibleCharacterLimit

The continuous p-adic character obtained by taking actual residue limits.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def compatibleCharacterLimit (χ : compatibleFiniteCharacters ξ ℓ) : padicCharacters ξ ℓ
EtaleFundamentalGroups.Cohomology.padicCharacterReduction

Reduction of a continuous p-adic character at a positive finite level.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def padicCharacterReduction (n : ℕ) (χ : padicCharacters ξ ℓ) :
    finiteLevelCharacters ξ ℓ n
EtaleFundamentalGroups.Cohomology.padicCharacterResidues

Simultaneous finite reductions of a p-adic character, as an additive homomorphism.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def padicCharacterResidues : padicCharacters ξ ℓ →+ compatibleFiniteCharacters ξ ℓ where
  toFun χ := ⟨fun n => padicCharacterReduction ξ ℓ n χ, fun n => by
    apply ContinuousMonoidHom.ext
    intro g
    exact congrArg (fun z => Multiplicative.ofAdd (ULift.up.{u} z))
      (congrArg (fun f : ℤ_[ℓ] →+* ZMod (ℓ ^ (n + 1)) => f (χ.toMul g).toAdd)
        (PadicInt.zmod_cast_comp_toZModPow (n + 1) (n + 2) (Nat.le_succ (n + 1))))⟩
  map_zero' := by
    apply Subtype.ext
    funext n
    apply ContinuousMonoidHom.ext
    intro g
    exact congrArg (fun z => Multiplicative.ofAdd (ULift.up.{u} z))
      (PadicInt.toZModPow (n + 1)).map_zero
  map_add' χ ψ := by
    apply Subtype.ext
    funext n
    apply ContinuousMonoidHom.ext
    intro g
    exact congrArg (fun z => Multiplicative.ofAdd (ULift.up.{u} z))
      ((PadicInt.toZModPow (n + 1)).map_add (χ.toMul g).toAdd (ψ.toMul g).toAdd)
EtaleFundamentalGroups.Cohomology.padicCharacterResidues_injective
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem padicCharacterResidues_injective :
    Function.Injective (padicCharacterResidues ξ ℓ)
EtaleFundamentalGroups.Cohomology.padicCharacterResidues_limit
Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
theorem padicCharacterResidues_limit (χ : compatibleFiniteCharacters ξ ℓ) :
    padicCharacterResidues ξ ℓ (compatibleCharacterLimit ξ ℓ χ) = χ
EtaleFundamentalGroups.Cohomology.padicCompatibleCharacterEquiv

Actual continuous p-adic characters are exactly compatible finite characters.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def padicCompatibleCharacterEquiv :
    padicCharacters ξ ℓ ≃+ compatibleFiniteCharacters ξ ℓ
EtaleFundamentalGroups.Cohomology.ellAdicH1PadicCharacterEquiv

Classical integral ℓ-adic H¹ of any connected scheme is the additive group of continuous ℤℓ-valued characters of its étale fundamental group.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def ellAdicH1PadicCharacterEquiv [ConnectedSpace X] [IsSepClosed Ω] :
    ellAdicCohomology X ℓ 1 ≃+ padicCharacters ξ ℓ
EtaleFundamentalGroups.Cohomology.padicAbelianCharacterEquiv

Restriction along the closed-commutator quotient identifies p-adic characters of the actual topological abelianization with fundamental-group characters.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def padicAbelianCharacterEquiv :
    Additive (TopologicalAbelianization (Aut (FiniteEtale.fiber ξ)) →ₜ*
      Multiplicative ℤ_[ℓ]) ≃+ padicCharacters ξ ℓ where
  toFun χ := Additive.ofMul (χ.toMul.comp
    (ProCGroups.Abelian.TopologicalAbelianization.mkₜ _))
  invFun χ := Additive.ofMul (ProCGroups.Abelian.TopologicalAbelianization.lift χ.toMul)
  left_inv χ := by
    apply ProCGroups.Abelian.TopologicalAbelianization.hom_ext
    intro g
    rfl
  right_inv χ := ContinuousMonoidHom.ext fun _ => rfl
  map_add' χ ψ := ContinuousMonoidHom.ext fun _ => rfl
EtaleFundamentalGroups.Cohomology.ellAdicH1AbelianPadicCharacterEquiv

Classical integral ℓ-adic H¹ is the group of continuous p-adic characters of the fundamental group's quotient by its closed commutator subgroup.

Source context 11 commands

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

noncomputable section
open AlgebraicGeometry CategoryTheory EtaleCohomology.Classical
open LocalFieldTheory.PadicResidues
open LocalFieldTheory.DiscreteValuationField.CompleteDVF.higherPrincipalUnitGroup.Internal
universe u
namespace EtaleFundamentalGroups.Cohomology
variable {X : Scheme.{u}}
  {Ω : Type u} [Field Ω] (ξ : Spec (.of Ω) ⟶ X)
  (ℓ : ℕ) [Fact ℓ.Prime]
local instance finiteCoefficientTopology (n : ℕ) :
    TopologicalSpace (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⊥
local instance finiteCoefficientDiscrete (n : ℕ) :
    DiscreteTopology (Multiplicative (ellPowerCoefficients.{u} ℓ n)) := ⟨rfl⟩
local instance residueTopology (n : ℕ) : TopologicalSpace (ZMod (ℓ ^ n)) := ⊥
local instance residueDiscrete (n : ℕ) : DiscreteTopology (ZMod (ℓ ^ n)) := ⟨rfl⟩
def ellAdicH1AbelianPadicCharacterEquiv [ConnectedSpace X] [IsSepClosed Ω] :
    ellAdicCohomology X ℓ 1 ≃+
      Additive (TopologicalAbelianization (Aut (FiniteEtale.fiber ξ)) →ₜ*
        Multiplicative ℤ_[ℓ])