Module

Defectless.lean

Nyll.ValuedFieldTheory.Valuation.DiscreteValuationField.FiniteExtension.Defectless
1 declaration indexed from sourceView source ↗

Defectlessness from a finite extension of valuation rings

The local Dedekind fundamental identity only needs discretely valued fields. Completeness and Henselianity play no role once the target valuation ring is a finite module over the base valuation ring.

Declarations

ValuationTheory.DiscreteValuationField.ValuedExtension.isDefectless_of_moduleFinite

A valued extension of discretely valued fields is defectless when its target valuation ring is finite over the base valuation ring.

Source context 4 commands

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

noncomputable section
namespace ValuationTheory.DiscreteValuationField.ValuedExtension
universe u v w x
variable {K : Type u} {L : Type w} [Field K] [Field L] [Algebra K L]
theorem isDefectless_of_moduleFinite
    (base : DVF.{u, v} K) (target : DVF.{w, x} L)
    [base.valuation.HasExtension target.valuation]
    [Module.Finite base.valuationSubring target.valuationSubring]
    [IsScalarTower base.valuationSubring target.valuationSubring L] :
    IsDefectless base target