Module

Localization.lean

Nyll.ClassFieldTheory.AlgebraicNumberTheory.Adele.IntegralTensorSupport.Localization
8 declarations indexed from sourceView source ↗

Localization of the relative integral lattice

Away from the finite exceptional set, this module compares the localized integer lattice with the integral closure and derives coordinatewise integrality after localization.

Declarations

Uniform local denominator statement: outside the bad set a denominator avoiding the prime carries every algebraic integer into the scaled lattice.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
theorem exists_notMem_smul_mem_scaledRelativeIntegerLattice
    (w : HeightOneSpectrum (𝓞 K))
    (hw : w ∉ integralTensorBadPlaces
      (K := K) (L := L))
    (x : 𝓞 L) :
    ∃ d : 𝓞 K, d ∉ w.asIdeal ∧
      d • x ∈
        scaledRelativeIntegerLattice
          (K := K) (L := L)

The local ring of K at a finite place.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
abbrev RelativeBaseIntegerLocalization
    (w : HeightOneSpectrum (𝓞 K))

The localization of 𝓞 L above the same finite place of K.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
abbrev RelativeExtensionIntegerLocalization
    (w : HeightOneSpectrum (𝓞 K))

The canonical localization map, regarded as an 𝓞 K-linear map.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
def relativeIntegerLocalizationLinearMap
    (w : HeightOneSpectrum (𝓞 K)) :
    𝓞 L →ₗ[𝓞 K]
      RelativeExtensionIntegerLocalization
        (K := K) (L := L) w

The span of the scaled integral relative basis after localization at a finite place of K.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
def localizedScaledRelativeIntegerLattice
    (w : HeightOneSpectrum (𝓞 K)) :
    Submodule
      (RelativeBaseIntegerLocalization (K := K) w)
      (RelativeExtensionIntegerLocalization
        (K := K) (L := L) w)

Every element of the global scaled lattice maps into its localized span.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
theorem relativeIntegerLocalizationLinearMap_mem_localizedLattice
    (w : HeightOneSpectrum (𝓞 K))
    {x : 𝓞 L}
    (hx : x ∈
      scaledRelativeIntegerLattice
        (K := K) (L := L)) :
    relativeIntegerLocalizationLinearMap
        (K := K) (L := L) w x ∈
      localizedScaledRelativeIntegerLattice
        (K := K) (L := L) w

Away from the finite bad set, every algebraic integer of L maps into the span of the scaled relative integral basis.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
theorem algebraMap_mem_localizedScaledRelativeIntegerLattice_of_notMem
    (w : HeightOneSpectrum (𝓞 K))
    (hw : w ∉ integralTensorBadPlaces
      (K := K) (L := L))
    (x : 𝓞 L) :
    algebraMap (𝓞 L)
        (RelativeExtensionIntegerLocalization
          (K := K) (L := L) w) x ∈
      localizedScaledRelativeIntegerLattice
        (K := K) (L := L) w

Outside the explicitly constructed finite set of bad places, the localized scaled lattice is the whole localization of 𝓞 L.

Source context 6 commands

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

open scoped NumberField TensorProduct NNReal
open NumberField IsDedekindDomain
noncomputable section
open AlgebraicNumberTheory.Valuations
universe u v
variable
    {K : Type u} {L : Type v}
    [Field K] [NumberField K]
    [Field L] [NumberField L] [Algebra K L]
    [FiniteDimensional K L]
theorem localizedScaledRelativeIntegerLattice_eq_top_of_notMem
    (w : HeightOneSpectrum (𝓞 K))
    (hw : w ∉ integralTensorBadPlaces
      (K := K) (L := L)) :
    localizedScaledRelativeIntegerLattice
        (K := K) (L := L) w = ⊤