Module

LocalReciprocityCharacterFixedField.lean

Nyll.SawinTotallyRealTowers.UnramifiedProPRelationRank.Kummer.LocalReciprocityCharacterFixedField
13 declarations indexed from sourceView source ↗

The finite local field cut out by a mod-p character

The finite abelian field is constructed from the character's actual open kernel. Its finite character recovers absolute Artin evaluation, and inertia-triviality puts inertia in the field's fixing subgroup.

Declarations

ClassFieldTower.Martinet.Shafarevich.localReciprocityFixedFieldTopology
Source context 6 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p)
ClassFieldTower.Martinet.Shafarevich.localReciprocityFixedFieldDiscreteTopology
Source context 7 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p)
ClassFieldTower.Martinet.Shafarevich.localReciprocityFixedFieldH1Module
Source context 8 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G))
ClassFieldTower.Martinet.Shafarevich.localReciprocitySeparableAbelianCharacter

The absolute character in the separable-closure abelianization model.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
def localReciprocitySeparableAbelianCharacter
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K)) :
    localAbsoluteAbelianProfinite K →ₜ* Multiplicative (ZMod p)
ClassFieldTower.Martinet.Shafarevich.localReciprocitySeparableAbelianCharacter_mk
Source context 10 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
omit [ValuativeRel K] [TopologicalSpace K] [IsNonarchimedeanLocalField K] in
theorem localReciprocitySeparableAbelianCharacter_mk
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K))
    (sigma : Gal(SeparableClosure K/K)) :
    localReciprocitySeparableAbelianCharacter K p chi (QuotientGroup.mk sigma) =
      Multiplicative.ofAdd
        (localStandardH1LinearEquivSeparable p K chi (Additive.ofMul sigma))
ClassFieldTower.Martinet.Shafarevich.localReciprocityCharacterKernel

The actual open kernel of the finite-valued abelian character.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
def localReciprocityCharacterKernel
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K)) :
    OpenNormalSubgroup (localAbsoluteAbelianProfinite K) where
  toSubgroup := (localReciprocitySeparableAbelianCharacter K p chi).toMonoidHom.ker
  isOpen' := (isOpen_discrete {1}).preimage
    (localReciprocitySeparableAbelianCharacter K p chi).continuous_toFun
  isNormal' := MonoidHom.normal_ker _
ClassFieldTower.Martinet.Shafarevich.localReciprocityCharacterField

The finite abelian extension cut out by the given local character.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
abbrev localReciprocityCharacterField
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K)) :
    IntermediateField K (SeparableClosure K)
ClassFieldTower.Martinet.Shafarevich.localReciprocityFiniteCharacter

The faithful character on the actual finite Galois group.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
def localReciprocityFiniteCharacter
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K)) :
    Gal(localReciprocityCharacterField K p chi / K) →* Multiplicative (ZMod p)
ClassFieldTower.Martinet.Shafarevich.localReciprocityFiniteCharacter_restriction

The finite character agrees with the original character after restriction.

Source context 10 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
omit [ValuativeRel K] [TopologicalSpace K] [IsNonarchimedeanLocalField K] in
theorem localReciprocityFiniteCharacter_restriction
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K))
    (x : localAbsoluteAbelianProfinite K) :
    localReciprocityFiniteCharacter K p chi
        (absoluteAbelianRestriction K (localReciprocityCharacterField K p chi) x) =
      localReciprocitySeparableAbelianCharacter K p chi x
ClassFieldTower.Martinet.Shafarevich.localReciprocityFiniteCharacter_artin

Actual finite Artin evaluation recovers the power-class pairing.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
theorem localReciprocityFiniteCharacter_artin
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K)) (a : Kˣ) :
    (localReciprocityFiniteCharacter K p chi
        (abelianLocalArtinMap K (localReciprocityCharacterField K p chi) a)).toAdd =
      localReciprocityH1PowerClassPairing K p chi
        (Additive.ofMul (QuotientGroup.mk' (powMonoidHom p : Kˣ →* Kˣ).range a))
ClassFieldTower.Martinet.Shafarevich.absoluteFiniteQuotientField_fixingSubgroup
Source context 10 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
omit [ValuativeRel K] [TopologicalSpace K] [IsNonarchimedeanLocalField K] in
theorem absoluteFiniteQuotientField_fixingSubgroup
    (N : OpenNormalSubgroup (localAbsoluteAbelianProfinite K)) :
    (absoluteFiniteQuotientField K N).fixingSubgroup =
      (absoluteFiniteQuotientPreimage K N).toSubgroup
ClassFieldTower.Martinet.Shafarevich.localIntrinsicUnramifiedH1_apply_inertia
Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
theorem localIntrinsicUnramifiedH1_apply_inertia
    (psi : ContinuousH1ZMod (p := p) (G := Gal(SeparableClosure K/K)))
    (hpsi : psi ∈ localIntrinsicUnramifiedH1 K p)
    (sigma : localIntrinsicInertiaSubgroup K) :
    psi (Additive.ofMul sigma.1) = 0
ClassFieldTower.Martinet.Shafarevich.localReciprocityCharacterField_inertia_le

An inertia-trivial character cuts out an inertia-fixed finite field.

Source context 9 commands

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

open scoped Topology
noncomputable section
namespace ClassFieldTower.Martinet.Shafarevich
open ClassFieldTower.ProP LocalClassFieldTheory
variable (K : Type) [Field K] [ValuativeRel K] [TopologicalSpace K]
  [IsNonarchimedeanLocalField K]
variable (p : ℕ) [Fact p.Prime]
local instance localReciprocityFixedFieldTopology : TopologicalSpace (ZMod p) := ⊥
local instance localReciprocityFixedFieldDiscreteTopology : DiscreteTopology (ZMod p) :=
  discreteTopology_bot _
local instance localReciprocityFixedFieldH1Module
    {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] :
    Module (ZMod p) (ContinuousH1ZMod (p := p) (G := G)) := continuousH1ZModModule
theorem localReciprocityCharacterField_inertia_le
    (chi : ContinuousH1ZMod (p := p) (G := Field.absoluteGaloisGroup K))
    (hchi : localStandardH1LinearEquivSeparable p K chi ∈
      localIntrinsicUnramifiedH1 K p) :
    MonoidHom.ker (localResidueDegree K).toMonoidHom ≤
      (localReciprocityCharacterField K p chi).fixingSubgroup