Module

FinitePlaceSeparableEmbedding.lean

Nyll.SawinTotallyRealTowers.UnramifiedProPRelationRank.Local.FinitePlaceSeparableEmbedding
6 declarations indexed from sourceView source ↗

The actual global-to-local separable-closure embedding

The chosen algebraic localization embeds the global algebraic closure into the local separable closure. Its pointwise equivariance identifies the actual action used by the decomposition-group comparison. Two canonical scalar towers are each installed once; no valuation preservation is assumed.

Declarations

ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbeddingBaseAlgebra
Source context 9 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv)
ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbeddingBaseTower
Source context 10 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
local instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv) :=
  Algebra.compHom (SeparableClosure Kv) (algebraMap F Kv)
instance finitePlaceSeparableEmbeddingBaseTower : IsScalarTower F Kv (SeparableClosure Kv)
ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbeddingAbsoluteAlgebra
Source context 11 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
local instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv) :=
  Algebra.compHom (SeparableClosure Kv) (algebraMap F Kv)
local instance finitePlaceSeparableEmbeddingBaseTower : IsScalarTower F Kv (SeparableClosure Kv) :=
  IsScalarTower.of_algebraMap_eq' rfl
instance finitePlaceSeparableEmbeddingAbsoluteAlgebra : Algebra F w.1.Completion
ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbeddingCompletionAlgebra
Source context 12 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
local instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv) :=
  Algebra.compHom (SeparableClosure Kv) (algebraMap F Kv)
local instance finitePlaceSeparableEmbeddingBaseTower : IsScalarTower F Kv (SeparableClosure Kv) :=
  IsScalarTower.of_algebraMap_eq' rfl
local instance finitePlaceSeparableEmbeddingAbsoluteAlgebra : Algebra F w.1.Completion :=
  AbsoluteValue.extensionCompletionAlgebra (K := F) w.1
instance finitePlaceSeparableEmbeddingCompletionAlgebra : Algebra Kv w.1.Completion
ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbedding

The selected global algebraic closure inside the local separable closure.

Source context 13 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
local instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv) :=
  Algebra.compHom (SeparableClosure Kv) (algebraMap F Kv)
local instance finitePlaceSeparableEmbeddingBaseTower : IsScalarTower F Kv (SeparableClosure Kv) :=
  IsScalarTower.of_algebraMap_eq' rfl
local instance finitePlaceSeparableEmbeddingAbsoluteAlgebra : Algebra F w.1.Completion :=
  AbsoluteValue.extensionCompletionAlgebra (K := F) w.1
local instance finitePlaceSeparableEmbeddingCompletionAlgebra : Algebra Kv w.1.Completion :=
  AbsoluteValue.completionAlgebra (HeightOneSpectrum.adicAbv F v) w.1 w.2
def finitePlaceSeparableEmbedding : AlgebraicClosure F →ₐ[F] SeparableClosure Kv where
  toRingHom := (finitePlaceAlgebraicLocalizationAlgEquivSeparableClosure F v).toRingHom.comp
    (AbsoluteValue.toAlgebraicLocalization (HeightOneSpectrum.adicAbv F v) w.1 w.2)
  commutes' x := by
    change (finitePlaceAlgebraicLocalizationAlgEquivSeparableClosure F v)
      (AbsoluteValue.toAlgebraicLocalization (HeightOneSpectrum.adicAbv F v) w.1 w.2
        (algebraMap F (AlgebraicClosure F) x)) = _
    rw [AbsoluteValue.toAlgebraicLocalization_algebraMap]
    exact (finitePlaceAlgebraicLocalizationAlgEquivSeparableClosure F v).commutes
      (algebraMap F Kv x)
ClassFieldTower.Martinet.Shafarevich.finitePlaceSeparableEmbedding_equivariant

Pointwise compatibility with the actual decomposition-group comparison.

Source context 13 commands

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

open NumberField IsDedekindDomain
open scoped NumberField
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open AlgebraicNumberTheory.Valuations HilbertRamification
variable (F : Type) [Field F] [NumberField F]
variable (v : HeightOneSpectrum (𝓞 F))
local notation "Kv" => AbsoluteValue.Completion (HeightOneSpectrum.adicAbv F v)
local notation "w" => finitePlaceAbsoluteValueExtension F v
local instance finitePlaceSeparableEmbeddingBaseAlgebra : Algebra F (SeparableClosure Kv) :=
  Algebra.compHom (SeparableClosure Kv) (algebraMap F Kv)
local instance finitePlaceSeparableEmbeddingBaseTower : IsScalarTower F Kv (SeparableClosure Kv) :=
  IsScalarTower.of_algebraMap_eq' rfl
local instance finitePlaceSeparableEmbeddingAbsoluteAlgebra : Algebra F w.1.Completion :=
  AbsoluteValue.extensionCompletionAlgebra (K := F) w.1
local instance finitePlaceSeparableEmbeddingCompletionAlgebra : Algebra Kv w.1.Completion :=
  AbsoluteValue.completionAlgebra (HeightOneSpectrum.adicAbv F v) w.1 w.2
theorem finitePlaceSeparableEmbedding_equivariant
    (sigma : finitePlaceAbsoluteDecompositionGroup F v) (x : AlgebraicClosure F) :
    finitePlaceDecompositionGroupContinuousMulEquivSeparableAbsoluteGaloisGroup F v sigma
        (finitePlaceSeparableEmbedding F v x) =
      finitePlaceSeparableEmbedding F v (sigma.1 x)