For monic `F ∈ O[X]`, the image of `F` in `K[X]` has polynomial type `σ` iff `O[X]/(F)` has algebra type `σ`.
ProvedTypeDensity.polynomial_type_iff_algebra_typetype-density
For monic F ∈ O[X], the image of F in K[X] has polynomial type σ iff O[X]/(F) has algebra type σ.
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Formula_LawAlgebra import Definitions.Def_TypeDensity_Algebra_AlgebraType import Definitions.Def_TypeDensity_Measure_AdicCylinders import Definitions.Def_TypeDensity_Measure_HenselProducts import Definitions.Def_TypeDensity_Unramified_Extension import Definitions.Def_TypeDensity_Measure_PrimitiveLocus import Definitions.Def_TypeDensity_Algebra_FactorInvariant import Theorems.Thm_TypeDensity_adjoinRoot_base_change import Theorems.Thm_TypeDensity_squarefree_of_isReduced_adjoinRoot import Theorems.Thm_TypeDensity_squarefree_monic_has_polynomial_type import Theorems.Thm_TypeDensity_integral_closure_algEquiv import Theorems.Thm_TypeDensity_pi_field_matching import Theorems.Thm_TypeDensity_algebra_type_unique import Theorems.Thm_TypeDensity_polynomial_quotient_product_equiv 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.RingTheory.Henselian import Mathlib.Topology.Algebra.MvPolynomial import Mathlib.Algebra.Group.Pi.Units import Mathlib.Order.CompletePartialOrder import Mathlib.RingTheory.Polynomial.Resultant.Basic import Mathlib.RingTheory.SimpleRing.Principal import Mathlib.Algebra.GroupWithZero.Submonoid.CancelMulZero import Mathlib.Algebra.Module.StablyFree.Basic import Mathlib.NumberTheory.Padics.RingHoms set_option autoImplicit false open TypeDensity open Polynomial
Formal statement
theorem TypeDensity.polynomial_type_iff_algebra_type (O : Type) [CommRing O] [IsDomain O]
[IsDiscreteValuationRing O] [IsAdicComplete (IsLocalRing.maximalIdeal O) O]
[Finite (IsLocalRing.ResidueField O)] (F : Polynomial O) (hF : F.Monic) (σ : FactorType) :
HasPolynomialTypeF O (F.map (algebraMap O (BaseField O))) σ ↔
HasAlgebraType O (AdjoinRoot F) σ := by sorrySource
TypeDensity/Algebra/FactorInvariant.lean#L273-L322