Module

LocalBlocks.lean

Nyll.ClassFieldTheory.AlgebraicNumberTheory.Idele.Cohomology.SPlaces.LocalBlocks
11 declarations indexed from sourceView source ↗

The local blocks occurring in a relative S-idele

For a finite set S of finite places, the unrestricted factors consist of every infinite place and the finite places in S. This file packages those two kinds of concrete tensor factors into one finite dependent family and identifies it equivariantly with the induced local blocks of the local tensor decomposition.

Declarations

A fixed infinite place of L above the given infinite place of K.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
def chosenInfinitePlaceAbove
    (v : InfinitePlace K) : InfinitePlace L

The chosen infinite place above v restricts back to v.

Source context 9 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
omit [NumberField K] [NumberField L] [FiniteDimensional K L] in
theorem chosenInfinitePlaceAbove_comap
    (v : InfinitePlace K) :
    (chosenInfinitePlaceAbove (L := L) v).comap
        (algebraMap K L) = v

Infinite places and the selected finite places form the finite unrestricted index family of a relative S-idele.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
abbrev RelativeUnrestrictedSPlaceIndex
    (S : Finset (HeightOneSpectrum (𝓞 K)))

The chosen local-place data at every unrestricted place.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
def relativeUnrestrictedSPlaceDatum
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    RelativeUnrestrictedSPlaceIndex (K := K) S →
      LocalPlaceDatum K L
  | Sum.inl v =>
      { base := v.1
        base_isNontrivial := v.isNontrivial
        extension :=
          infinitePlaceAbsoluteValueExtension
            v (chosenInfinitePlaceAbove (L := L) v)
            (chosenInfinitePlaceAbove_comap
              (L := L) v) }
  | Sum.inr v =>
      { base := HeightOneSpectrum.adicAbv K v.1
        base_isNontrivial :=
          RayClass.adicAbv_isNontrivial v.1
        extension :=
          chosenFinitePlaceExtension
            (L := L) v.1 }

The actual tensor-unit type attached to one unrestricted place.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
abbrev RelativeUnrestrictedSPlaceFactor
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    RelativeUnrestrictedSPlaceIndex (K := K) S → Type
  | Sum.inl v => (v.Completion ⊗[K] L)ˣ
  | Sum.inr v => (v.1.adicCompletion K ⊗[K] L)ˣ

Each unrestricted local tensor-unit factor is a commutative group.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
instance relativeUnrestrictedSPlaceFactorCommGroup
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (i : RelativeUnrestrictedSPlaceIndex (K := K) S) :
    CommGroup
      (RelativeUnrestrictedSPlaceFactor
        (K := K) (L := L) S i)

The finite family of actual unrestricted tensor factors.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
abbrev RelativeUnrestrictedSPlaceFactors
    (S : Finset (HeightOneSpectrum (𝓞 K)))

The componentwise scalar-conjugation action on the unrestricted tensor factors.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
def relativeUnrestrictedSPlaceFactorsAction
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    MulDistribMulAction (L ≃ₐ[K] L)
      (RelativeUnrestrictedSPlaceFactors
        (K := K) (L := L) S)

The componentwise local tensor equivalence for every unrestricted place in S.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
def
    relativeUnrestrictedSPlaceFactorsEquivLocalBlockFamily
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    RelativeUnrestrictedSPlaceFactors
        (K := K) (L := L) S ≃*
      LocalBlockFamily
        (relativeUnrestrictedSPlaceDatum
          (K := K) (L := L) S)

The unrestricted-factor realization is equivariant for the full global Galois action.

Source context 9 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
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
    relativeUnrestrictedSPlaceFactorsEquivLocalBlockFamily_smul
    (S : Finset (HeightOneSpectrum (𝓞 K)))
    (σ : L ≃ₐ[K] L)
    (z : RelativeUnrestrictedSPlaceFactors
      (K := K) (L := L) S) :
    relativeUnrestrictedSPlaceFactorsEquivLocalBlockFamily
        (K := K) (L := L) S
        ((relativeUnrestrictedSPlaceFactorsAction
          (K := K) (L := L) S).smul σ z) =
      (localBlockFamilyAction
          (relativeUnrestrictedSPlaceDatum
            (K := K) (L := L) S)).smul σ
        (relativeUnrestrictedSPlaceFactorsEquivLocalBlockFamily
          (K := K) (L := L) S z)

Reassociate the displayed unrestricted factors of RelativeIdeleSPlaceFactors as the finite dependent family above.

Source context 8 commands

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

open scoped NumberField TensorProduct
open NumberField IsDedekindDomain
noncomputable section
open LocalClassFieldTheory
open AlgebraicNumberTheory.Valuations
open CyclicCohomology
open HilbertRamification
variable {K L : Type}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L] [IsGalois K L]
def relativeUnrestrictedSPlaceFactorsEquivProd
    (S : Finset (HeightOneSpectrum (𝓞 K))) :
    RelativeUnrestrictedSPlaceFactors
        (K := K) (L := L) S ≃*
      (∀ v : InfinitePlace K,
          (v.Completion ⊗[K] L)ˣ) ×
        (∀ v :
          {v : HeightOneSpectrum (𝓞 K) // v ∈ S},
          (v.1.adicCompletion K ⊗[K] L)ˣ) where
  toFun z :=
    ⟨fun v => z (Sum.inl v),
      fun v => z (Sum.inr v)⟩
  invFun z
    | Sum.inl v => z.1 v
    | Sum.inr v => z.2 v
  left_inv z := by
    funext i
    cases i <;> rfl
  right_inv _ := rfl
  map_mul' _ _ := rfl