Module

EtaleLifting.lean

Nyll.ValuedFieldTheory.Valuation.Henselian.EtaleLifting
1 declaration indexed from sourceView source ↗

Lifting residue points of etale algebras

At the kernel of a residue point, an etale algebra has a standard etale localization. The Henselian root lift on that localization restricts to the requested lift on the original algebra.

Declarations

ValuationTheory.Henselian.exists_etale_lift

A residue point of an etale algebra over a Henselian local pair lifts to an actual point over the base ring.

Source context 2 commands

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

namespace ValuationTheory.Henselian
variable {R S : Type*} [CommRing R] [CommRing S] [Algebra R S]
  {I : Ideal R} [I.IsMaximal] [HenselianRing R I] [Algebra.Etale R S]
theorem exists_etale_lift (σ : S →ₐ[R] R ⧸ I) :
    ∃ τ : S →ₐ[R] R, (Ideal.Quotient.mkₐ R I).comp τ = σ