Module

OrientedConsequences.lean

Nyll.Yamaguchi26AbfaithfulGalois.FormalHilbert90.OrientedConsequences
2 declarations indexed from sourceView source ↗

Torsion and fixed classes under relative formal Hilbert 90

Declarations

Yamaguchi26AbfaithfulGalois.primaryAbelianization_isMulTorsionFree

The primary abelianization of the orientation kernel is torsion-free.

Source context 2 commands

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

namespace Yamaguchi26AbfaithfulGalois
universe u
theorem primaryAbelianization_isMulTorsionFree
    {ℓ : ℕ} [Fact ℓ.Prime]
    {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
    (D : Subgroup G) [D.Normal] (hDclosed : IsClosed (D : Set G))
    (θ : Orientation ℓ G) (hDθ : D ≤ θ.toMonoidHom.ker)
    (hLift : RelativeFormalHilbert90 D θ) :
    IsMulTorsionFree (PrimaryAbelianization ℓ D)
Yamaguchi26AbfaithfulGalois.primaryFixedSubgroup_eq_bot_of_infinite_orientation

Infinite orientation image forces every open-subgroup fixed part to vanish.

Source context 2 commands

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

namespace Yamaguchi26AbfaithfulGalois
universe u
theorem primaryFixedSubgroup_eq_bot_of_infinite_orientation
    {ℓ : ℕ} [Fact ℓ.Prime]
    {G : Type u} [Group G] [TopologicalSpace G] [IsTopologicalGroup G]
    [CompactSpace G] [T2Space G] [TotallyDisconnectedSpace G]
    (D : Subgroup G) [D.Normal] (hDclosed : IsClosed (D : Set G))
    (θ : Orientation ℓ G) (hDθ : D ≤ θ.toMonoidHom.ker)
    (hLift : RelativeFormalHilbert90 D θ) (hθ : Set.Infinite (Set.range θ))
    (H : OpenSubgroup G) : primaryFixedSubgroup ℓ D hDclosed (H : Subgroup G) = ⊥