**Quadratic projective densities.** For every `q > 1`, the universal projective expressions of degree `2` take the values `1/2` (split), `(q² - q + 1) / (2(q² + q + 1))` (inert) and `q / (q² + q + 1)`
ProvedTypeDensity.Tests.projectiveExpr_two_evaltype-density
Quadratic projective densities. For every q > 1, the universal projective expressions of degree 2 take the values 1/2 (split), (q² - q + 1) / (2(q² + q + 1)) (inert) and q / (q² + q + 1) (ramified), and vanish on every other type.
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Blowup_Directions import Definitions.Def_TypeDensity_Measure_AdicCylinders import Definitions.Def_TypeDensity_Formula_LawAlgebra 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_Formula_PatternCounts 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 Definitions.Def_TypeDensity_Surfaces_TruncatedSeries import Definitions.Def_TypeDensity_Blowup_TwoChartCurveData import Definitions.Def_TypeDensity_Surfaces_ConcreteAtlas import Definitions.Def_TypeDensity_Recursion_Members import Definitions.Def_TypeDensity_Measure_MemberCharts import Definitions.Def_TypeDensity_Recursion_Termination import Definitions.Def_TypeDensity_Recursion_OrderDefect import Definitions.Def_TypeDensity_Assembly_NullBridges import Definitions.Def_TypeDensity_Assembly_TypeEvents import Definitions.Def_TypeDensity_Assembly_MonicCells import Definitions.Def_TypeDensity_Blowup_DivisorPoints import Definitions.Def_TypeDensity_Measure_MemberBoxes import Definitions.Def_TypeDensity_Recursion_ChildMembers import Definitions.Def_TypeDensity_Recursion_RootCellLaw import Definitions.Def_TypeDensity_Reciprocity_Defs import Definitions.Def_TypeDensity_Reciprocity_Quantum import Definitions.Def_TypeDensity_Reciprocity_Patterns import Definitions.Def_TypeDensity_Tests_NonVacuity import Definitions.Def_TypeDensity_Tests_Regression import Theorems.Thm_TypeDensity_Tests_divisorCount_spat import Theorems.Thm_TypeDensity_Tests_single_two_law import Theorems.Thm_TypeDensity_Tests_coeff_globalLaw_two 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.FieldTheory.Finite.GaloisField import Mathlib.RingTheory.AdicCompletion.Algebra import Mathlib.RingTheory.RegularLocalRing.Defs 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 import Mathlib.Algebra.Azumaya.Basic import Mathlib.RingTheory.AdicCompletion.RingHom import Mathlib.RingTheory.TotallySplit import Mathlib.RingTheory.AdicCompletion.LocalRing import Mathlib.RingTheory.KrullDimension.NonZeroDivisors import Mathlib.Algebra.Group.NatPowAssoc import Mathlib.Algebra.Order.Ring.Star import Mathlib.Data.Int.Star import Mathlib.LinearAlgebra.Dimension.Torsion.Finite import Mathlib.RingTheory.PowerSeries.Expand import Mathlib.RingTheory.PowerSeries.Log import Mathlib.RingTheory.PowerSeries.PiTopology import Mathlib.Data.Finsupp.Encodable import Mathlib.Topology.Connected.Separation import Mathlib.Topology.Instances.ZMod import Mathlib.Topology.Separation.Lemmas set_option autoImplicit false open TypeDensity TypeDensity.Tests set_option autoImplicit false open scoped BigOperators ENNReal
Formal statement
theorem TypeDensity.Tests.projectiveExpr_two_eval (q : ℚ) (hq : 1 < q) (σ : FactorType) :
(projectiveExpr 2 σ).eval q =
(if σ = {(1,1), (1,1)} then 1 / 2 else 0) +
(if σ = {(1,2)} then (q ^ 2 - q + 1) / (2 * (q ^ 2 + q + 1)) else 0) +
(if σ = {(2,1)} then q / (q ^ 2 + q + 1) else 0) := by sorrySource
Tests/Regression.lean#L1154-L1170