Module

Factors.lean

Nyll.ClassFieldTheory.AlgebraicNumberTheory.Idele.Cohomology.SPlaces.Herbrand.Factors
9 declarations indexed from sourceView source ↗

Transport from local blocks to unrestricted factors

This leaf transports the finite-family Herbrand calculation to the actual unrestricted relative S-idele factors.

Canonical factor-transport action providers

Declarations

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
def
    relativeUnrestrictedSPlaceFactorsActionProvider
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    MulDistribMulAction (L ≃ₐ[K] L)
      (RelativeUnrestrictedSPlaceFactors
        (K := K) (L := L) S)
Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
def
    relativeUnrestrictedSPlaceLocalBlockFamilyActionProvider
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    MulDistribMulAction (L ≃ₐ[K] L)
      (LocalBlockFamily
        (relativeUnrestrictedSPlaceDatum
          (K := K) (L := L) S))

The equivariant realization by local blocks identifies degree-zero Herbrand cohomology of the actual unrestricted factors with that of the local-block family.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
def
    relativeUnrestrictedSPlaceFactorsHerbrandH0EquivLocalBlockFamily
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    @HerbrandH0 (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S)
        _ _ _
        (relativeUnrestrictedSPlaceFactorsAction
          (K := K) (L := L) S) ≃*
      @HerbrandH0 (L ≃ₐ[K] L)
        (LocalBlockFamily
          (relativeUnrestrictedSPlaceDatum
            (K := K) (L := L) S))
        _ _ _
        (localBlockFamilyAction
          (relativeUnrestrictedSPlaceDatum
            (K := K) (L := L) S))

The equivariant realization by local blocks identifies degree-minus-one Herbrand cohomology of the actual unrestricted factors with that of the local-block family.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
def
    relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneEquivLocalBlockFamily
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L) :
    @HerbrandHMinusOne (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S)
        _ _ _
        (relativeUnrestrictedSPlaceFactorsAction
          (K := K) (L := L) S) σ ≃*
      @HerbrandHMinusOne (L ≃ₐ[K] L)
        (LocalBlockFamily
          (relativeUnrestrictedSPlaceDatum
            (K := K) (L := L) S))
        _ _ _
        (localBlockFamilyAction
          (relativeUnrestrictedSPlaceDatum
            (K := K) (L := L) S)) σ

Degree-zero cohomology of the actual unrestricted tensor factors is finite.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
theorem relativeUnrestrictedSPlaceFactorsHerbrandH0Finite
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (hgen : ∀ τ : L ≃ₐ[K] L,
      τ ∈ Subgroup.zpowers σ) :
    letI :=
      relativeUnrestrictedSPlaceFactorsAction
        (K := K) (L := L) S
    Finite
      (HerbrandH0 (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S)) := by
  let d :=
    relativeUnrestrictedSPlaceDatum
      (K := K) (L := L) S
  let sourceAction :=
    relativeUnrestrictedSPlaceFactorsActionProvider
      (K := K) (L := L) S
  let targetAction :=
    relativeUnrestrictedSPlaceLocalBlockFamilyActionProvider
      (K := K) (L := L) S
  let targetFinite : Finite
      (HerbrandH0 (L ≃ₐ[K] L)
        (LocalBlockFamily d)) :=
    relativeUnrestrictedLocalBlockFamilyHerbrandH0Finite
      S σ hgen
  exact
    Finite.of_equiv
      (HerbrandH0 (L ≃ₐ[K] L)
        (LocalBlockFamily d))
      (relativeUnrestrictedSPlaceFactorsHerbrandH0EquivLocalBlockFamily
        (K := K) (L := L) S).symm.toEquiv

Degree-minus-one cohomology of the actual unrestricted tensor factors is finite.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
theorem relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneFinite
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (hgen : ∀ τ : L ≃ₐ[K] L,
      τ ∈ Subgroup.zpowers σ) :
    letI :=
      relativeUnrestrictedSPlaceFactorsAction
        (K := K) (L := L) S
    Finite
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S) σ) := by
  let d :=
    relativeUnrestrictedSPlaceDatum
      (K := K) (L := L) S
  let sourceAction :=
    relativeUnrestrictedSPlaceFactorsActionProvider
      (K := K) (L := L) S
  let targetAction :=
    relativeUnrestrictedSPlaceLocalBlockFamilyActionProvider
      (K := K) (L := L) S
  let targetFinite : Finite
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (LocalBlockFamily d) σ) :=
    relativeUnrestrictedLocalBlockFamilyHerbrandHMinusOneFinite
      S σ hgen
  exact
    Finite.of_equiv
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (LocalBlockFamily d) σ)
      (relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneEquivLocalBlockFamily
        (K := K) (L := L) S σ).symm.toEquiv

Degree zero for the actual unrestricted factors: its cardinality is the product of the local degrees.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
theorem
    relativeUnrestrictedSPlaceFactorsHerbrandH0_card_eq_product
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (hgen : ∀ τ : L ≃ₐ[K] L,
      τ ∈ Subgroup.zpowers σ) :
    letI :=
      relativeUnrestrictedSPlaceFactorsAction
        (K := K) (L := L) S
    letI : Finite
        (HerbrandH0 (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S)) :=
      relativeUnrestrictedSPlaceFactorsHerbrandH0Finite
        S σ hgen
    Nat.card
        (HerbrandH0 (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S)) =
      ∏ i,
        relativeUnrestrictedSPlaceLocalDegree
          (K := K) (L := L) S i := by
  let d :=
    relativeUnrestrictedSPlaceDatum
      (K := K) (L := L) S
  let sourceAction :=
    relativeUnrestrictedSPlaceFactorsActionProvider
      (K := K) (L := L) S
  let targetAction :=
    relativeUnrestrictedSPlaceLocalBlockFamilyActionProvider
      (K := K) (L := L) S
  let sourceFinite : Finite
      (HerbrandH0 (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S)) :=
    relativeUnrestrictedSPlaceFactorsHerbrandH0Finite
      S σ hgen
  let targetFinite : Finite
      (HerbrandH0 (L ≃ₐ[K] L)
        (LocalBlockFamily d)) :=
    relativeUnrestrictedLocalBlockFamilyHerbrandH0Finite
      S σ hgen
  calc
    Nat.card
        (HerbrandH0 (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S)) =
      Nat.card
        (HerbrandH0 (L ≃ₐ[K] L)
          (LocalBlockFamily d)) :=
      Nat.card_congr
        (relativeUnrestrictedSPlaceFactorsHerbrandH0EquivLocalBlockFamily
          (K := K) (L := L) S).toEquiv
    _ = ∏ i,
        relativeUnrestrictedSPlaceLocalDegree
          (K := K) (L := L) S i :=
      relativeUnrestrictedLocalBlockFamilyHerbrandH0_card_eq_product
        S σ hgen

Degree minus one for the actual unrestricted factors: the group has one element.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
theorem
    relativeUnrestrictedSPlaceFactorsHerbrandHMinusOne_card_eq_one
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (hgen : ∀ τ : L ≃ₐ[K] L,
      τ ∈ Subgroup.zpowers σ) :
    letI :=
      relativeUnrestrictedSPlaceFactorsAction
        (K := K) (L := L) S
    letI : Finite
        (HerbrandHMinusOne (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S) σ) :=
      relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneFinite
        S σ hgen
    Nat.card
        (HerbrandHMinusOne (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S) σ) = 1 := by
  let d :=
    relativeUnrestrictedSPlaceDatum
      (K := K) (L := L) S
  let sourceAction :=
    relativeUnrestrictedSPlaceFactorsActionProvider
      (K := K) (L := L) S
  let targetAction :=
    relativeUnrestrictedSPlaceLocalBlockFamilyActionProvider
      (K := K) (L := L) S
  let sourceFinite : Finite
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S) σ) :=
    relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneFinite
      S σ hgen
  let targetFinite : Finite
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (LocalBlockFamily d) σ) :=
    relativeUnrestrictedLocalBlockFamilyHerbrandHMinusOneFinite
      S σ hgen
  calc
    Nat.card
        (HerbrandHMinusOne (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S) σ) =
      Nat.card
        (HerbrandHMinusOne (L ≃ₐ[K] L)
          (LocalBlockFamily d) σ) :=
      Nat.card_congr
        (relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneEquivLocalBlockFamily
          (K := K) (L := L) S σ).toEquiv
    _ = 1 :=
      relativeUnrestrictedLocalBlockFamilyHerbrandHMinusOne_card_eq_one
        S σ hgen

The Herbrand quotient formula for the actual unrestricted tensor factors.

Source context 11 commands

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

open scoped NumberField BigOperators ValuativeRel NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
open CyclicCohomology.ProfiniteCohomology.Herbrand
open CyclicCohomology
open HilbertRamification
open LocalClassFieldTheory
open LocalFieldTheory
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField L] in
theorem relativeUnrestrictedSPlaceFactors_herbrandQuotient
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (hgen : ∀ τ : L ≃ₐ[K] L,
      τ ∈ Subgroup.zpowers σ) :
    letI :=
      relativeUnrestrictedSPlaceFactorsAction
        (K := K) (L := L) S
    letI : Finite
        (HerbrandH0 (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S)) :=
      relativeUnrestrictedSPlaceFactorsHerbrandH0Finite
        S σ hgen
    letI : Finite
        (HerbrandHMinusOne (L ≃ₐ[K] L)
          (RelativeUnrestrictedSPlaceFactors
            (K := K) (L := L) S) σ) :=
      relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneFinite
        S σ hgen
    herbrandQuotient
        (G := L ≃ₐ[K] L)
        (A := RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S) σ =
      ∏ i,
        (relativeUnrestrictedSPlaceLocalDegree
          (K := K) (L := L) S i : ℚ) := by
  let :=
    relativeUnrestrictedSPlaceFactorsAction
      (K := K) (L := L) S
  let : Finite
      (HerbrandH0 (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S)) :=
    relativeUnrestrictedSPlaceFactorsHerbrandH0Finite
      S σ hgen
  let : Finite
      (HerbrandHMinusOne (L ≃ₐ[K] L)
        (RelativeUnrestrictedSPlaceFactors
          (K := K) (L := L) S) σ) :=
    relativeUnrestrictedSPlaceFactorsHerbrandHMinusOneFinite
      S σ hgen
  rw [herbrandQuotient_eq_card_ratio,
    relativeUnrestrictedSPlaceFactorsHerbrandH0_card_eq_product
      S σ hgen,
    relativeUnrestrictedSPlaceFactorsHerbrandHMinusOne_card_eq_one
      S σ hgen]
  simp only [Nat.cast_prod, Nat.cast_one, div_one]