Module

MaximalQuotientResidueConjugate.lean

Nyll.SchemeTheory.RingTheory.Ramification.MaximalQuotientResidueConjugate
1 declaration indexed from sourceView source ↗

Conjugacy of quotient and localization residue maps

Identifies the residue automorphism of a localization as the conjugate of the quotient automorphism through the canonical maximal-quotient residue equivalence.

Declarations

EtaleFundamentalGroups.Inertia.maximalQuotientResidueEquiv_localization_conjugate

The actual localization residue map is conjugate to its quotient map through the fixed canonical maximal-quotient equivalence.

Source context 3 commands

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

noncomputable section
namespace EtaleFundamentalGroups.Inertia
universe u
theorem maximalQuotientResidueEquiv_localization_conjugate
    {B : Type u} [CommRing B] (Q : Ideal B) [Q.IsMaximal]
    (e : B ≃+* B) (hQ : Q = Q.comap e.toRingHom) :
    (IsLocalRing.ResidueField.mapEquiv
        (Localization.localRingEquiv Q Q e hQ)).toRingHom =
      ((maximalQuotientResidueEquiv Q).toRingHom.comp
        (Ideal.quotientEquiv Q Q e
          ((congrArg (Ideal.map e.toRingHom) hQ).trans
            (Ideal.map_comap_eq_self_of_equiv e Q)).symm).toRingHom).comp
        (maximalQuotientResidueEquiv Q).symm.toRingHom