For a Noetherian local ring `(A, m)` with completion `Â`, the quotient `Â/(m Â)^L` is `A`-isomorphic to `A/m^L`, compatibly with the maps from `A`.
ProvedTypeDensity.local_completion_finite_quotienttype-density
For a Noetherian local ring (A, m) with completion Â, the quotient Â/(m Â)^L is A-isomorphic to A/m^L, compatibly with the maps from A.
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Blowup_Directions import Definitions.Def_TypeDensity_Measure_AdicCylinders import Definitions.Def_TypeDensity_Measure_HenselProducts import Definitions.Def_TypeDensity_Surfaces_Lengths import Definitions.Def_TypeDensity_Unramified_Extension import Definitions.Def_TypeDensity_Blowup_Charts import Definitions.Def_TypeDensity_Formula_LawAlgebra import Definitions.Def_TypeDensity_Surfaces_PowerSeries import Mathlib.FieldTheory.RatFunc.Basic import Mathlib.MeasureTheory.Measure.Haar.Unique import Mathlib.NumberTheory.ArithmeticFunction.Moebius import Mathlib.NumberTheory.Padics.PadicIntegers import Mathlib.RingTheory.IntegralClosure.IntegralRestrict import Mathlib.RingTheory.MvPowerSeries.Basic import Mathlib.RingTheory.RamificationInertia.Basic import Mathlib.Topology.Algebra.Nonarchimedean.AdicTopology import Mathlib.Topology.Algebra.MvPolynomial import Mathlib.Algebra.Group.Pi.Units import Mathlib.Order.CompletePartialOrder import Mathlib.RingTheory.Henselian import Mathlib.RingTheory.Polynomial.Resultant.Basic import Mathlib.RingTheory.RegularLocalRing.Defs import Mathlib.RingTheory.SimpleRing.Principal import Mathlib.FieldTheory.Finite.Extension import Mathlib.RingTheory.AdicCompletion.Noetherian import Mathlib.RingTheory.MvPowerSeries.Equiv import Mathlib.RingTheory.PicardGroup import Mathlib.FieldTheory.Finite.GaloisField import Mathlib.RingTheory.AdicCompletion.Algebra import Mathlib.RingTheory.AdicCompletion.Completeness set_option autoImplicit false open TypeDensity
Formal statement
theorem TypeDensity.local_completion_finite_quotient (A : Type) [CommRing A] [IsNoetherianRing A]
[IsLocalRing A] (L : ℕ) :
∃ E : (LocalCompletion A ⧸ ((IsLocalRing.maximalIdeal A).map (localCompletionMap A))^L) ≃ₐ[A]
(A ⧸ (IsLocalRing.maximalIdeal A)^L), ∀ a : A,
E (Ideal.Quotient.mk (((IsLocalRing.maximalIdeal A).map (localCompletionMap A))^L)
(localCompletionMap A a)) = Ideal.Quotient.mk ((IsLocalRing.maximalIdeal A)^L) a := by sorrySource
TypeDensity/Unramified/LocalDescent.lean#L94-L118