Every maximal ideal of the chart containing `t` is the direction point of an affine direction `φ` over the residue field;
ProvedTypeDensity.chart_point_eq_directionPointtype-density
Every maximal ideal of the chart containing t is the direction point of an affine direction φ over the residue field; it maps onto (φ) in the exceptional fibre and contains the slope iff φ is the zero direction.
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_Formula_FiniteFieldCounts import Definitions.Def_TypeDensity_Formula_StateCombinatorics import Definitions.Def_TypeDensity_Blowup_Directions import Definitions.Def_TypeDensity_Unramified_Extension import Definitions.Def_TypeDensity_Blowup_Charts import Definitions.Def_TypeDensity_Algebra_AlgebraType import Definitions.Def_TypeDensity_Measure_PrimitiveLocus import Definitions.Def_TypeDensity_Algebra_FactorInvariant import Theorems.Thm_TypeDensity_blowup_chart_exceptional_point_polynomial 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.FieldTheory.RatFunc.AsPolynomial import Mathlib.RingTheory.AdicCompletion.Completeness import Mathlib.Algebra.GroupWithZero.Submonoid.CancelMulZero import Mathlib.Algebra.Module.StablyFree.Basic import Mathlib.NumberTheory.Padics.RingHoms set_option autoImplicit false open TypeDensity open scoped BigOperators ENNReal
Formal statement
theorem TypeDensity.chart_point_eq_directionPoint (R : Type) [CommRing R] [IsLocalRing R] (t x : R)
[(Ideal.span ({t,x} : Set R)).IsMaximal]
(e : (BlowupChart R t x ⧸ chartExceptional R t x) ≃+* Polynomial (IsLocalRing.ResidueField R))
(he : ∀ r : R, e (Ideal.Quotient.mk (chartExceptional R t x) (chartBase R t x r)) =
Polynomial.C (IsLocalRing.residue R r))
(heZ : e (Ideal.Quotient.mk (chartExceptional R t x) (chartSlope R t x)) = Polynomial.X)
(P : Ideal (BlowupChart R t x)) [P.IsMaximal] (hP : chartBase R t x t ∈ P) :
∃ φ : AffineDirection (IsLocalRing.ResidueField R), P = directionPoint R t x e φ ∧
(P.map (Ideal.Quotient.mk (chartExceptional R t x))).map e = Ideal.span {φ.val} ∧
(chartSlope R t x ∈ P ↔ φ = zeroAffine (IsLocalRing.ResidueField R)) := by sorrySource
TypeDensity/Blowup/ExceptionalLayers.lean#L436-L501