Module

UnitQuotientGalois.lean

Nyll.ClassFieldTheory.LubinTate.EqualCharacteristic.FiniteLevel.UnitQuotientGalois
18 declarations indexed from sourceView source ↗

Equal-characteristic Lubin--Tate unit quotients and Galois groups

This file constructs the finite-level Galois action of a power-series unit with the local-Artin orientation: a sends the chosen primitive generator to [a⁻¹]. Its kernel is the (n + 1)-st higher-unit subgroup, so the action descends to a multiplicative equivalence from the finite unit quotient to the Galois group.

Imports72
Imported by3

Declarations

LubinTate.equalCharacteristicLubinTateArtinUnitLevelRoot

The finite-level root obtained from the Artin-oriented bracket [a⁻¹].

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
def equalCharacteristicLubinTateArtinUnitLevelRoot
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateLevelField F n
LubinTate.equalCharacteristicLubinTateArtinUnitLevelRoot_aeval_minpoly

The Artin-oriented unit root annihilates the generator's minimal polynomial.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitLevelRoot_aeval_minpoly
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    Polynomial.aeval
        (equalCharacteristicLubinTateArtinUnitLevelRoot F n a)
        (minpoly F.residueField⸨X⸩
          (equalCharacteristicLubinTateLevelPowerBasis F n).gen) = 0
LubinTate.equalCharacteristicLubinTateArtinUnitAlgHom

The finite-level algebra endomorphism with Artin orientation.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
def equalCharacteristicLubinTateArtinUnitAlgHom
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateLevelField F n →ₐ[F.residueField⸨X⸩]
      equalCharacteristicLubinTateLevelField F n
LubinTate.equalCharacteristicLubinTateArtinUnitAlgHom_apply_gen
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitAlgHom_apply_gen
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitAlgHom F n a
        (equalCharacteristicLubinTateLevelPowerBasis F n).gen =
      equalCharacteristicLubinTateArtinUnitLevelRoot F n a
LubinTate.equalCharacteristicLubinTateArtinUnitAlgEquiv

The finite-level Galois automorphism whose generator action is [a⁻¹].

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
def equalCharacteristicLubinTateArtinUnitAlgEquiv
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateLevelField F n ≃ₐ[F.residueField⸨X⸩]
      equalCharacteristicLubinTateLevelField F n
LubinTate.equalCharacteristicLubinTateArtinUnitAlgEquiv_apply_gen
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitAlgEquiv_apply_gen
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitAlgEquiv F n a
        (equalCharacteristicLubinTateLevelPowerBasis F n).gen =
      equalCharacteristicLubinTateArtinUnitLevelRoot F n a
LubinTate.equalCharacteristicLubinTateArtinUnitAlgEquiv_one
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitAlgEquiv_one
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) :
    equalCharacteristicLubinTateArtinUnitAlgEquiv F n 1 = 1
LubinTate.equalCharacteristicLubinTateArtinUnitAlgEquiv_mul
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitAlgEquiv_mul
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a b : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitAlgEquiv F n (a * b) =
      equalCharacteristicLubinTateArtinUnitAlgEquiv F n a *
        equalCharacteristicLubinTateArtinUnitAlgEquiv F n b
LubinTate.equalCharacteristicLubinTateArtinUnitToGal

Power-series units acting on the finite Lubin--Tate level with Artin orientation.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
def equalCharacteristicLubinTateArtinUnitToGal
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) :
    F.residueField⟦X⟧ˣ →*
      Gal((equalCharacteristicLubinTateLevelField F n) /
        F.residueField⸨X⸩) where
  toFun := equalCharacteristicLubinTateArtinUnitAlgEquiv F n
  map_one' := equalCharacteristicLubinTateArtinUnitAlgEquiv_one F n
  map_mul' := equalCharacteristicLubinTateArtinUnitAlgEquiv_mul F n
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_apply_gen
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_apply_gen
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitToGal F n a
        (equalCharacteristicLubinTateLevelPowerBasis F n).gen =
      equalCharacteristicLubinTateArtinUnitLevelRoot F n a
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_ker

The kernel of the Artin-oriented explicit unit action is the level higher-unit subgroup.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_ker
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) :
    MonoidHom.ker (equalCharacteristicLubinTateArtinUnitToGal F n) =
      equalCharacteristicLubinTateHigherUnitSubgroup F n
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_parameterUnit_inv

A visible finite parameter is obtained from the Artin-oriented unit action by inverting its represented power-series unit.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_parameterUnit_inv
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (p : equalCharacteristicLubinTateUnitParameter F n) :
    equalCharacteristicLubinTateArtinUnitToGal F n
        (equalCharacteristicLubinTateUnitParameterUnit F n p)⁻¹ =
      equalCharacteristicLubinTateUnitParameterAlgEquiv F n p
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_surjective

Every finite-level Galois automorphism is induced by an Artin-oriented power-series unit.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_surjective
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) :
    Function.Surjective
      (equalCharacteristicLubinTateArtinUnitToGal F n)
LubinTate.equalCharacteristicLubinTateArtinUnitQuotientEquivGal

The Artin-oriented explicit finite-level reciprocity equivalence from the unit quotient.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
def equalCharacteristicLubinTateArtinUnitQuotientEquivGal
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) :
    F.residueField⟦X⟧ˣ ⧸
        equalCharacteristicLubinTateHigherUnitSubgroup F n ≃*
      Gal((equalCharacteristicLubinTateLevelField F n) /
        F.residueField⸨X⸩)
LubinTate.equalCharacteristicLubinTateArtinUnitQuotientEquivGal_mk
Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitQuotientEquivGal_mk
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitQuotientEquivGal F n
        (QuotientGroup.mk a) =
      equalCharacteristicLubinTateArtinUnitToGal F n a
LubinTate.equalCharacteristicLubinTateArtinUnitQuotientEquivGal_mk_apply_gen_coe

On a representative, the quotient-to-Galois equivalence is the inverse orientation of the existing quotient action on the primitive torsion point.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem
    equalCharacteristicLubinTateArtinUnitQuotientEquivGal_mk_apply_gen_coe
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    ((equalCharacteristicLubinTateArtinUnitQuotientEquivGal F n
          (QuotientGroup.mk a))
        (equalCharacteristicLubinTateLevelPowerBasis F n).gen :
      SeparableClosure F.residueField⸨X⸩) =
      (equalCharacteristicLubinTateUnitQuotientAutomorphismEquiv F n
        (QuotientGroup.mk a⁻¹)
        (⟨chosenEqualCharacteristicLubinTatePrimitiveRoot F n,
          chosenEqualCharacteristicLubinTatePrimitiveRoot_torsion F n⟩ :
          equalCharacteristicLubinTateAmbientTorsionAddSubgroup F
            (equalCharacteristicSeparableUniformizer F) (n + 1))).1
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_eq_one_iff

Kernel membership in pointwise form.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_eq_one_iff
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitToGal F n a = 1 ↔
      a ∈ equalCharacteristicLubinTateHigherUnitSubgroup F n
LubinTate.equalCharacteristicLubinTateArtinUnitToGal_eq_one_iff_sub_one_mem

The explicit congruence criterion for trivial finite-level action.

Source context 7 commands

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

noncomputable section
open scoped LaurentSeries PowerSeries Polynomial
universe u v
namespace LubinTate
open LocalFieldTheory.DiscreteValuationField
open LubinTate.EqualCharacteristic
variable {K : Type u} [Field K]
theorem equalCharacteristicLubinTateArtinUnitToGal_eq_one_iff_sub_one_mem
    (F : LocalField.{u, v} K)
    [CharP K F.residueCharacteristic]
    (n : ℕ) (a : F.residueField⟦X⟧ˣ) :
    equalCharacteristicLubinTateArtinUnitToGal F n a = 1 ↔
      (a : F.residueField⟦X⟧) - 1 ∈
        Ideal.span
          ({PowerSeries.X ^ (n + 1)} : Set F.residueField⟦X⟧)