The projective normalizer evaluates to `1 + q + ⋯ + q^n`, and `(1 + ⋯ + q^n)(q − 1) = q^(n+1) − 1`.
ProvedTypeDensity.projective_normalizer_evaltype-density
The projective normalizer evaluates to 1 + q + ⋯ + q^n, and (1 + ⋯ + q^n)(q − 1) = q^(n+1) − 1.
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 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 scoped ENNReal
Formal statement
theorem TypeDensity.projective_normalizer_eval (q : ℚ) (n : ℕ) :
(projectiveNormalizer n).eval q = ∑ i ∈ Finset.range (n+1), q ^ i ∧
(∑ i ∈ Finset.range (n+1), q ^ i) * (q - 1) = q ^ (n+1) - 1 := by sorrySource
TypeDensity/Unramified/PolynomialTypes.lean#L769-L792