Module

AddVal.lean

Nyll.ValuedFieldTheory.Valuation.DiscreteValuationField.AddVal
2 declarations indexed from sourceView source ↗

Normalized additive valuations on discrete valuation rings

This file supplies general-purpose facts about Mathlib's normalized additive valuation on a discrete valuation ring which are independent of any chosen valued-field presentation.

Declarations

IsDiscreteValuationRing.mem_maximalIdeal_pow_iff_addVal_ge

Membership in a power of the maximal ideal is detected by the normalized additive valuation.

Source context 4 commands

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

noncomputable section
universe u
namespace IsDiscreteValuationRing
variable {R : Type u} [CommRing R] [IsDomain R] [IsDiscreteValuationRing R]
theorem mem_maximalIdeal_pow_iff_addVal_ge (a : R) (n : ℕ) :
    a ∈ IsLocalRing.maximalIdeal R ^ n ↔ (n : ℕ∞) ≤ addVal R a
IsDiscreteValuationRing.addVal_ringEquiv

A ring automorphism of a discrete valuation ring preserves its normalized additive valuation.

Source context 4 commands

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

noncomputable section
universe u
namespace IsDiscreteValuationRing
variable {R : Type u} [CommRing R] [IsDomain R] [IsDiscreteValuationRing R]
theorem addVal_ringEquiv (e : R ≃+* R) (a : R) :
    addVal R (e a) = addVal R a