Module

IntrinsicAbsoluteData.lean

Nyll.ClassFieldTheory.LocalClassFieldTheory.Finite.LocalReciprocity.IntrinsicAbsoluteData
7 declarations indexed from sourceView source ↗

Intrinsic absolute Galois data

This module packages the absolute Galois group of a field, its integral unit representation, and its distinguished abstract base field using the chosen separable closure.

Imports2
Imported by29

Declarations

LocalClassFieldTheory.intrinsicAbsoluteGalois

The absolute Galois group of a field, formed using its chosen separable closure.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
abbrev intrinsicAbsoluteGalois
    (F : Type) [Field F]
LocalClassFieldTheory.intrinsicAbsoluteUnits

The integral representation of the intrinsic absolute Galois group on the units of the chosen separable closure.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
abbrev intrinsicAbsoluteUnits
    (F : Type) [Field F] :
    Rep ℤ (intrinsicAbsoluteGalois F)
LocalClassFieldTheory.intrinsicAbstractBase

The closed base subgroup of the intrinsic absolute Galois group, expressed as the fixing subgroup of the bottom intermediate field.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
abbrev intrinsicAbstractBase
    (F : Type) [Field F] :
    ClosedSubgroup (intrinsicAbsoluteGalois F)
LocalClassFieldTheory.intrinsicAbstractBaseEquivAbsolute

The canonical equivalence from the intrinsic abstract base subgroup to the full absolute Galois group.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
def intrinsicAbstractBaseEquivAbsolute
    (F : Type) [Field F] :
    (intrinsicAbstractBase F).toSubgroup ≃*
      intrinsicAbsoluteGalois F
LocalClassFieldTheory.intrinsicAbstractBaseEquivAbsolute_symm_apply_val

The inverse intrinsic-base equivalence has underlying automorphism equal to the supplied absolute Galois automorphism.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
theorem intrinsicAbstractBaseEquivAbsolute_symm_apply_val
    (F : Type) [Field F] (σ : intrinsicAbsoluteGalois F) :
    ((intrinsicAbstractBaseEquivAbsolute F).symm σ).1 = σ
LocalClassFieldTheory.intrinsicFiniteAbstractBase

The intrinsic abstract base packaged as a finite abstract field; its defining quotient is the trivial finite quotient.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
def intrinsicFiniteAbstractBase
    (F : Type) [Field F] :
    FiniteAbstractField (intrinsicAbsoluteGalois F) where
  field := intrinsicAbstractBase F
  finite := by
    rw [intrinsicAbstractBase, closedFixingSubgroup_bot_eq_baseField]
    exact (FiniteAbstractField.base (intrinsicAbsoluteGalois F)).finite
LocalClassFieldTheory.intrinsicFiniteAbstractBase_eq_base

The finite intrinsic base is the distinguished finite base of the abstract class formation.

Source context 4 commands

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

noncomputable section
namespace LocalClassFieldTheory
open RamificationTheory CyclicCohomology KummerTheory
open ClassFormation
theorem intrinsicFiniteAbstractBase_eq_base
    (F : Type) [Field F] :
    intrinsicFiniteAbstractBase F =
      FiniteAbstractField.base (intrinsicAbsoluteGalois F)