Every binary form of degree `∑ d i` is `∑ h i ∏_{j ≠ i} g j + c ∏ g i` with `h i (ν i) = 0` (partial fractions for pairwise coprime binary forms).
ProvedTypeDensity.forms_linear_bijectivetype-density
Every binary form of degree ∑ d i is ∑ h i ∏_{j ≠ i} g j + c ∏ g i with h i (ν i) = 0 (partial fractions for pairwise coprime binary forms).
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Measure_AdicCylinders import Definitions.Def_TypeDensity_Measure_HenselProducts import Definitions.Def_TypeDensity_Unramified_Extension import Theorems.Thm_TypeDensity_formPoly_add import Theorems.Thm_TypeDensity_forms_linear_injective 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.Algebra.Group.Pi.Units import Mathlib.Order.CompletePartialOrder import Mathlib.RingTheory.Henselian import Mathlib.RingTheory.Polynomial.Resultant.Basic import Mathlib.RingTheory.RegularLocalRing.Defs import Mathlib.RingTheory.SimpleRing.Principal set_option autoImplicit false open TypeDensity open Polynomial IsLocalRing MeasureTheory open scoped Classical
Formal statement
theorem TypeDensity.forms_linear_bijective (k ι : Type) [Field k] [Fintype ι] (d : ι → ℕ)
(g : ∀ i, Fin (d i + 1) → k) (hg : ∀ i, g i ≠ 0) (hc : FormsCoprime d g)
(ν : ∀ i, Fin (d i + 1)) (hν : ∀ i, g i (ν i) ≠ 0) (w : Fin ((∑ i, d i) + 1) → k) :
∃ (h : ∀ i, Fin (d i + 1) → k) (c : k), (∀ i, h i (ν i) = 0) ∧ formPoly w = ∑ i, formPoly
(h i) * ∏ j ∈ Finset.univ.erase i, formPoly (g j) + Polynomial.C c * ∏ i, formPoly (g i) := by sorrySource
TypeDensity/Unramified/Extension.lean#L865-L953