Module

IdeleClassDirectLimitFiniteTowerNormStatement.lean

Nyll.ClassFieldTheory.GlobalClassFieldTheory.Reciprocity.IdeleClassDirectLimitFiniteTowerNormStatement
4 declarations indexed from sourceView source ↗

Ordinary norms in finite towers of rational fixed fields

This leaf compares the abstract relative norm in the rational idèle-class direct limit with the ordinary idèle-class norm for a finite fixed-field tower. The upper field need not be Galois over the lower field.

The construction is kept separate from the foundational direct-limit norm module so that the normal-closure and coset-product proof elaborates in a fresh command environment.

Declarations

GlobalClassFieldTheory.Reciprocity.rationalFixedFieldAbsoluteQuotient

The finite absolute quotient attached to a rational fixed field.

Source context 7 commands

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

noncomputable section
namespace GlobalClassFieldTheory
namespace Reciprocity
open ClassFormation
open LocalClassFieldTheory
open CyclicCohomology
open FiniteTowerNormCore
abbrev rationalFixedFieldAbsoluteQuotient
    (K : ClosedSubgroup
      (SeparableClosure ℚ ≃ₐ[ℚ] SeparableClosure ℚ))
GlobalClassFieldTheory.Reciprocity.rationalFixedFieldRelativeQuotient

The finite relative quotient attached to an inclusion of rational fixed fields.

Source context 7 commands

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

noncomputable section
namespace GlobalClassFieldTheory
namespace Reciprocity
open ClassFormation
open LocalClassFieldTheory
open CyclicCohomology
open FiniteTowerNormCore
abbrev rationalFixedFieldRelativeQuotient
    (K L : ClosedSubgroup
      (SeparableClosure ℚ ≃ₐ[ℚ] SeparableClosure ℚ))
    (hLK : L.toSubgroup ≤ K.toSubgroup)
GlobalClassFieldTheory.Reciprocity.rationalAbstractRelativeFixedFieldNormStatement

The proposition that the abstract relative norm agrees with the ordinary idele-class norm on a finite tower of rational fixed fields.

Source context 7 commands

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

noncomputable section
namespace GlobalClassFieldTheory
namespace Reciprocity
open ClassFormation
open LocalClassFieldTheory
open CyclicCohomology
open FiniteTowerNormCore
def
    rationalAbstractRelativeFixedFieldNormStatement
    (K L : ClosedSubgroup
      (SeparableClosure ℚ ≃ₐ[ℚ] SeparableClosure ℚ))
    (hLK : L.toSubgroup ≤ K.toSubgroup)
    [hKfinite : Finite (rationalFixedFieldAbsoluteQuotient K)]
    [hfinite : Finite
      (rationalFixedFieldRelativeQuotient K L hLK)] : Prop
GlobalClassFieldTheory.Reciprocity.rationalRelativeFixedFieldCosetActionStatement

The pointwise comparison between the abstract coset action and the ordinary class embedding into a common rational normal closure.

Source context 7 commands

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

noncomputable section
namespace GlobalClassFieldTheory
namespace Reciprocity
open ClassFormation
open LocalClassFieldTheory
open CyclicCohomology
open FiniteTowerNormCore
def
    rationalRelativeFixedFieldCosetActionStatement
    (K L : ClosedSubgroup
      (SeparableClosure ℚ ≃ₐ[ℚ] SeparableClosure ℚ))
    (hLK : L.toSubgroup ≤ K.toSubgroup)
    [hKfinite : Finite (rationalFixedFieldAbsoluteQuotient K)]
    [hfinite : Finite
      (rationalFixedFieldRelativeQuotient K L hLK)] : Prop