The unramified coefficient measure on `O[X]/(Φ)` is an additive Haar probability measure, and the ball `x + (base ideal)^L` has mass `q^(-δL)`.
ProvedTypeDensity.unramified_coefficient_measure_haartype-density
The unramified coefficient measure on O[X]/(Φ) is an additive Haar probability measure, and the ball x + (base ideal)^L has mass q^(-δL).
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 Theorems.Thm_TypeDensity_power_coordinates_transport import Theorems.Thm_TypeDensity_coefficient_cylinder_mass import Theorems.Thm_TypeDensity_coefficient_measure_probability import Theorems.Thm_TypeDensity_base_ideal_coordinates 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 MeasureTheory open scoped BigOperators ENNReal
Formal statement
theorem TypeDensity.unramified_coefficient_measure_haar (O : Type) [CommRing O] [IsDomain O]
[TopologicalSpace O] [IsTopologicalRing O] [CompactSpace O] [T2Space O]
[SecondCountableTopology O] [MeasurableSpace O] [BorelSpace O] (Φ : Polynomial O) (hm : Φ.Monic)
[TopologicalSpace (AdjoinRoot Φ)]
(hτ : ‹TopologicalSpace (AdjoinRoot Φ)› = unramifiedTopology O Φ hm)
[MeasurableSpace (AdjoinRoot Φ)]
(hmeas : ‹MeasurableSpace (AdjoinRoot Φ)› = unramifiedMeasurableSpace O Φ hm)
[IsDiscreteValuationRing O] [IsAdicComplete (IsLocalRing.maximalIdeal O) O]
[Finite (IsLocalRing.ResidueField O)] (htop : IsAdic (IsLocalRing.maximalIdeal O)) :
Measure.IsAddHaarMeasure (unramifiedCoefficientMeasure O Φ hm) ∧
IsProbabilityMeasure (unramifiedCoefficientMeasure O Φ hm) ∧ ∀ (L : ℕ) (x : AdjoinRoot Φ),
unramifiedCoefficientMeasure O Φ hm {y | y - x ∈ (baseIdeal O Φ) ^ L} =
(Nat.card (IsLocalRing.ResidueField O) : ℝ≥0∞)⁻¹ ^ (Φ.natDegree * L) := by sorrySource
TypeDensity/Measure/PrimitiveLocus.lean#L147-L189