Module

ValueImage.lean

Nyll.SchemeTheory.AbhyankarLemma.TameRamification.ValueGroup.NonarchimedeanLocalField.Galois.Ramification.ValueImage
12 declarations indexed from sourceView source ↗

Galois ramification value images

This file identifies the exact value images generated by embedded base units and their [M : L]-powered lower-branch images using Neu1999 Galois valuation data.

Declarations

TameAbhyankar.NAField.galois_mapBaseUnitsToExtensionUnits_valuation_formula

Neu1999's Galois valuation data, rewritten for the packaged MultiplicativeIntegerValuation: embedding a base unit into the extension multiplies its valuation by the supplied ramification index.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem galois_mapBaseUnitsToExtensionUnits_valuation_formula
    (x : Kˣ) :
    (multiplicativeIntegerValuation L).val
        (LocalFieldTheory.IsNonarchimedeanLocalField.mapBaseUnitsToExtensionUnits K L x) =
      (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ) *
        (multiplicativeIntegerValuation K).val x
TameAbhyankar.NAField.galois_mapBaseUnitsToExtensionUnits_uniformizer_val

A base uniformizer maps to an extension unit whose valuation is exactly the Galois ramification index supplied by Neu1999.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem galois_mapBaseUnitsToExtensionUnits_uniformizer_val
    {ϖ : Kˣ} (hϖ : (multiplicativeIntegerValuation K).IsUniformizer ϖ) :
    (multiplicativeIntegerValuation L).val
        (LocalFieldTheory.IsNonarchimedeanLocalField.mapBaseUnitsToExtensionUnits K L ϖ) =
      (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.exists_baseUnitsImageSubgroup_val_galoisRamificationIndex

A concrete embedded base unit generates the Neu1999 Galois ramification index in the extension valuation group.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem exists_baseUnitsImageSubgroup_val_galoisRamificationIndex :
    ∃ x : Lˣ,
      x ∈ baseUnitsImageSubgroup (K := K) (L := L) ∧
        (multiplicativeIntegerValuation L).val x =
          (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.integerMultipleSubgroup_galoisRamificationIndex_le_baseUnitsImage

Subgroup-image form of the Galois ramification generator: the integer subgroup generated by the Neu1999 Galois ramification index lies in the value image of embedded base units.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem integerMultipleSubgroup_galoisRamificationIndex_le_baseUnitsImage :
    integerMultipleSubgroup
        (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ) ≤
      (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (baseUnitsImageSubgroup (K := K) (L := L))
TameAbhyankar.NAField.baseUnitsImageSubgroup_valueImage_le_galoisRamificationIndex

Every valuation value appearing on the embedded-base-unit subgroup is a multiple of the Neu1999 Galois ramification index.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem baseUnitsImageSubgroup_valueImage_le_galoisRamificationIndex :
    (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (baseUnitsImageSubgroup (K := K) (L := L)) ≤
      integerMultipleSubgroup
        (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.baseUnitsImageSubgroup_valueImage_eq_galoisRamificationIndex

Exact value image of the embedded-base-unit subgroup in a finite Galois Neu1999 local-field extension.

Source context 14 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
theorem baseUnitsImageSubgroup_valueImage_eq_galoisRamificationIndex :
    (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (baseUnitsImageSubgroup (K := K) (L := L)) =
      integerMultipleSubgroup
        (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.exists_mem_fieldNormSubgroup_val_finrank_mul_galoisRamificationIndex

A base uniformizer, embedded in L and then powered by [M : L], produces a concrete element of fieldNormSubgroup L M whose L-valuation is [M : L] times the Neu1999 Galois ramification index of L/K.

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem exists_mem_fieldNormSubgroup_val_finrank_mul_galoisRamificationIndex :
    ∃ x : Lˣ,
      x ∈ fieldNormSubgroup L M ∧
        (multiplicativeIntegerValuation L).val x =
          (Module.finrank L M : ℤ) *
            (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.integerMultipleSubgroup_finrank_mul_galoisRamificationIndex_le_fieldNormSubgroup

Subgroup-image form of the powered norm generator. The integer subgroup generated by [M : L] * e_gal(L/K) lies in the value image of fieldNormSubgroup L M.

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem integerMultipleSubgroup_finrank_mul_galoisRamificationIndex_le_fieldNormSubgroup :
    integerMultipleSubgroup
        ((Module.finrank L M : ℤ) *
          (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)) ≤
      (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (fieldNormSubgroup L M)
TameAbhyankar.NAField.exists_mem_poweredBaseUnitsImageSubgroup_val_finrank_mul_galoisRamificationIndex

A concrete powered embedded base unit generates the value step [M : L] * e_gal(L/K).

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem exists_mem_poweredBaseUnitsImageSubgroup_val_finrank_mul_galoisRamificationIndex :
    ∃ x : Lˣ,
      x ∈ poweredBaseUnitsImageSubgroup (K := K) (L := L) (M := M) ∧
        (multiplicativeIntegerValuation L).val x =
          (Module.finrank L M : ℤ) *
            (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)
TameAbhyankar.NAField.integerMultipleSubgroup_finrank_mul_galoisRamificationIndex_le_poweredBaseUnitsImage

The integer subgroup generated by [M : L] * e_gal(L/K) lies in the value image of the powered embedded-base-unit subgroup.

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem integerMultipleSubgroup_finrank_mul_galoisRamificationIndex_le_poweredBaseUnitsImage :
    integerMultipleSubgroup
        ((Module.finrank L M : ℤ) *
          (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ)) ≤
      (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (poweredBaseUnitsImageSubgroup (K := K) (L := L) (M := M))
TameAbhyankar.NAField.poweredBaseUnitsImageSubgroup_valueImage_le_finrank_mul_galoisRamificationIndex

Every value appearing on the powered embedded-base-unit subgroup is a multiple of [M : L] * e_gal(L/K).

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem poweredBaseUnitsImageSubgroup_valueImage_le_finrank_mul_galoisRamificationIndex :
    (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (poweredBaseUnitsImageSubgroup (K := K) (L := L) (M := M)) ≤
      integerMultipleSubgroup
        ((Module.finrank L M : ℤ) *
          (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ))
TameAbhyankar.NAField.poweredBaseUnitsImageSubgroup_valueImage_eq_finrank_mul_galoisRamificationIndex

Exact value image of the powered embedded-base-unit subgroup.

Source context 16 commands

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

noncomputable section
universe u
namespace TameAbhyankar
open LocalFieldTheory.DiscreteValuationField
open scoped ValuativeRel
namespace NAField
variable {K L : Type u}
variable [Field K] [Field L] [Algebra K L]
variable [ValuativeRel K] [TopologicalSpace K]
variable [IsNonarchimedeanLocalField K]
variable [ValuativeRel L] [TopologicalSpace L]
variable [IsNonarchimedeanLocalField L]
variable [FiniteDimensional K L] [IsGalois K L]
variable [Valuation.HasExtension (ValuativeRel.valuation K)
  (ValuativeRel.valuation L)]
section NormTower
variable {M : Type u} [Field M] [Algebra L M]
theorem poweredBaseUnitsImageSubgroup_valueImage_eq_finrank_mul_galoisRamificationIndex :
    (multiplicativeIntegerValuation L).subgroupValueSubgroup
        (poweredBaseUnitsImageSubgroup (K := K) (L := L) (M := M)) =
      integerMultipleSubgroup
        ((Module.finrank L M : ℤ) *
          (Ideal.ramificationIdx (𝓂[L] : Ideal 𝒪[L]) 𝒪[K] : ℤ))