Module

ModPrimeCohomologyDetection.lean

Nyll.Yamaguchi26AbfaithfulGalois.Kummer.ModPrimeCohomologyDetection
1 declaration indexed from sourceView source ↗

Detecting cohomology actions from moved mod-prime classes

A moved mod-prime abelianization class yields a nontrivial relative Galois cohomology action. The inverse automorphism reflects contravariant pullback.

Declarations

Yamaguchi26AbfaithfulGalois.inverse_relativeH1Action_ne_one_of_moved_abelianModPower

A moved mod-prime abelianization class gives a nontrivial action on H¹. The inverse appears because the cohomology action uses inverse pullback.

Source context 3 commands

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

namespace Yamaguchi26AbfaithfulGalois
open KummerTheory ProCGroups.Abelian ClassFieldTower.ProP
universe u
theorem inverse_relativeH1Action_ne_one_of_moved_abelianModPower
    (K L : Type u) [Field K] [Field L] [Algebra K L] [CharZero L]
    (p : ℕ) [Fact p.Prime] (τ : Gal(L/K))
    (z : abelianModPower Gal(AlgebraicClosure L/L) p)
    (hz : relativeGaloisAbelianModPowerTransform K L p τ z ≠ z) :
    relativeGaloisH1Action (n := p) K L τ⁻¹ ≠ 1