Let `e` be a non-zero-divisor of a noetherian local ring `S` with `S / (e) ≃ k[[X]]`, and let `g` have nonzero image in `k[[X]]`.
ProvedTypeDensity.transverse_of_reduction_ne_zerotype-density
Let e be a non-zero-divisor of a noetherian local ring S with S / (e) ≃ k[[X]], and let g have nonzero image in k[[X]]. Then e is a non-zero-divisor modulo g, g is a non-zero-divisor modulo e, and (g, e) contains a power of the maximal ideal.
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Formula_LawAlgebra import Definitions.Def_TypeDensity_Measure_AdicCylinders import Definitions.Def_TypeDensity_Measure_HenselProducts import Definitions.Def_TypeDensity_Surfaces_Lengths import Definitions.Def_TypeDensity_Surfaces_PowerSeries import Definitions.Def_TypeDensity_Algebra_AlgebraType import Definitions.Def_TypeDensity_Unramified_Extension import Definitions.Def_TypeDensity_Measure_PrimitiveLocus import Definitions.Def_TypeDensity_Algebra_FactorInvariant 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.FieldTheory.Finite.GaloisField import Mathlib.RingTheory.AdicCompletion.Algebra import Mathlib.RingTheory.RegularLocalRing.Defs 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.SimpleRing.Principal import Mathlib.FieldTheory.Finite.Extension import Mathlib.RingTheory.AdicCompletion.Noetherian import Mathlib.RingTheory.MvPowerSeries.Equiv import Mathlib.RingTheory.PicardGroup import Mathlib.Algebra.GroupWithZero.Submonoid.CancelMulZero import Mathlib.Algebra.Module.StablyFree.Basic import Mathlib.NumberTheory.Padics.RingHoms import Mathlib.Algebra.Azumaya.Basic import Mathlib.RingTheory.AdicCompletion.Completeness import Mathlib.RingTheory.AdicCompletion.RingHom import Mathlib.RingTheory.TotallySplit set_option autoImplicit false open TypeDensity
Formal statement
theorem TypeDensity.transverse_of_reduction_ne_zero (S : Type) [CommRing S] [IsLocalRing S]
[IsNoetherianRing S] (e g : S) (hereg : Function.Injective (fun y : S ↦ e * y)) (k : Type)
[Field k] (q : (S ⧸ Ideal.span {e}) ≃+* PowerSeries k)
(hg : q (Ideal.Quotient.mk (Ideal.span {e}) g) ≠ 0) :
Function.Injective (fun a : S ⧸ Ideal.span {g} ↦ Ideal.Quotient.mk (Ideal.span {g}) e * a) ∧
Function.Injective
(fun a : S ⧸ Ideal.span {e} ↦ Ideal.Quotient.mk (Ideal.span {e}) g * a) ∧
∃ L : ℕ, (IsLocalRing.maximalIdeal S)^L ≤ Ideal.span {g, e} := by sorrySource
TypeDensity/Surfaces/Completeness.lean#L100-L150