OAI/AlgebraicGeometry/PlaneCurves/Gluing.lean

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25 declarations, 0 contain sorry, 0 declared as axioms

Holomorphic local division and gluing on multiplier quotient bundles

  1. theorem OAI.Nagata.LocalDivision.exists_analytic_quotient_at_simple_zero line 27

    Source documentation

    Dividing by a power of a function with a simple zero produces an analytic germ precisely when the numerator has sufficient vanishing. This constructs the germ, rather than assuming a global quotient exists.

    theorem exists_analytic_quotient_at_simple_zero {f P : ℂ → ℂ} {z₀ : ℂ}
        (hf : AnalyticAt ℂ f z₀) (hP : AnalyticAt ℂ P z₀)
        (hP0 : P z₀ = 0) (hP' : deriv P z₀ ≠ 0) (k : ℕ)
        (horder : (k : ℕ∞) ≤ analyticOrderAt f z₀) :
        ∃ g : ℂ → ℂ, AnalyticAt ℂ g z₀ ∧
          ∀ᶠ z in 𝓝 z₀, f z = P z ^ k * g z := by
    …
  2. theorem OAI.Nagata.LocalDivision.analytic_quotient_at_nonzero line 45

    Source documentation

    Away from the zero divisor, the usual pointwise quotient is analytic.

    theorem analytic_quotient_at_nonzero {f P : ℂ → ℂ} {z₀ : ℂ}
        (hf : AnalyticAt ℂ f z₀) (hP : AnalyticAt ℂ P z₀)
        (hP0 : P z₀ ≠ 0) (k : ℕ) :
        AnalyticAt ℂ (fun z => f z / P z ^ k) z₀ :=
    …
  3. theorem OAI.Nagata.LocalDivision.exists_analytic_quotient line 53

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    One uniform local-division statement handles both marked points and their complement. The derivative condition is needed only at a zero of P.

    theorem exists_analytic_quotient {f P : ℂ → ℂ} {z₀ : ℂ}
        (hf : AnalyticAt ℂ f z₀) (hP : AnalyticAt ℂ P z₀) (k : ℕ)
        (hzero : P z₀ = 0 → deriv P z₀ ≠ 0 ∧
          (k : ℕ∞) ≤ analyticOrderAt f z₀) :
        ∃ g : ℂ → ℂ, AnalyticAt ℂ g z₀ ∧
          ∀ᶠ z in 𝓝 z₀, f z = P z ^ k * g z := by
    …
  4. theorem OAI.Nagata.LocalDivision.analytic_quotient_germ_unique line 79

    Source documentation

    Local quotient germs are unique wherever the denominator is not the zero germ.

    theorem analytic_quotient_germ_unique {f P g h : ℂ → ℂ} {z₀ : ℂ} (k : ℕ)
        (hP : AnalyticAt ℂ P z₀) (hPfin : analyticOrderAt P z₀ ≠ ⊤)
        (hg : AnalyticAt ℂ g z₀) (hh : AnalyticAt ℂ h z₀)
        (hfg : ∀ᶠ z in 𝓝 z₀, f z = P z ^ k * g z)
        (hfh : ∀ᶠ z in 𝓝 z₀, f z = P z ^ k * h z) :
        g =ᶠ[𝓝 z₀] h := by
    …
  5. theorem OAI.Nagata.LocalDivision.continuous_eq_at_of_eq_off_divisor line 96

    Source documentation

    A continuous identity known off a nonzero analytic divisor extends across its zero set. This is used to recover multiplier transition identities after gluing.

    theorem continuous_eq_at_of_eq_off_divisor {P g h : ℂ → ℂ} {U : Set ℂ} {z₀ : ℂ}
        (hU : IsOpen U) (hz₀ : z₀ ∈ U) (hP : AnalyticAt ℂ P z₀)
        (hPfin : analyticOrderAt P z₀ ≠ ⊤) (hg : ContinuousAt g z₀)
        (hh : ContinuousAt h z₀)
        (heq : ∀ z ∈ U, P z ≠ 0 → g z = h z) : g z₀ = h z₀ := by
    …
  6. theorem OAI.Nagata.LocalDivision.multiply_power_injective_on line 114

    Source documentation

    Multiplication by P^k is injective on continuous functions on U when P has no zero germ. This is the noncancellation needed for the positive-index blocks.

    theorem multiply_power_injective_on {P f g : ℂ → ℂ} {U : Set ℂ}
        (hU : IsOpen U) (k : ℕ) (hP : AnalyticOnNhd ℂ P U)
        (hPfin : ∀ z ∈ U, analyticOrderAt P z ≠ ⊤)
        (hf : ∀ z ∈ U, ContinuousAt f z) (hg : ∀ z ∈ U, ContinuousAt g z)
        (hmul : ∀ z ∈ U, P z ^ k * f z = P z ^ k * g z) :
        Set.EqOn f g U := by
    …
  7. theorem OAI.Nagata.LocalDivision.multiply_power_nonzero line 128

    Source documentation

    Consequently an actual nonzero coefficient does not vanish identically when multiplied by a marked-product power.

    theorem multiply_power_nonzero {P f : ℂ → ℂ} {U : Set ℂ}
        (hU : IsOpen U) (k : ℕ) (hP : AnalyticOnNhd ℂ P U)
        (hPfin : ∀ z ∈ U, analyticOrderAt P z ≠ ⊤)
        (hf : ∀ z ∈ U, ContinuousAt f z) (hne : ∃ z ∈ U, f z ≠ 0) :
        ∃ z ∈ U, P z ^ k * f z ≠ 0 := by
    …
  8. theorem OAI.Nagata.LocalDivision.glue_analytic_quotients line 147

    Source documentation

    Compatible local quotient germs glue to a genuine global analytic function on any open domain. Uniqueness was proved above by ordinary analytic cancellation.

    theorem glue_analytic_quotients {f P : ℂ → ℂ} {U : Set ℂ} (hU : IsOpen U)
        (k : ℕ) (hP : AnalyticOnNhd ℂ P U)
        (hPfin : ∀ z ∈ U, analyticOrderAt P z ≠ ⊤)
        (hlocal : ∀ z ∈ U, ∃ g : ℂ → ℂ, AnalyticAt ℂ g z ∧
          ∀ᶠ w in 𝓝 z, f w = P w ^ k * g w) :
        ∃ G : ℂ → ℂ, AnalyticOnNhd ℂ G U ∧
          (∀ z ∈ U, f z = P z ^ k * G z) ∧ (∀ z ∉ U, G z = 0) := by
    …
  9. theorem OAI.Nagata.LocalDivision.exists_global_analytic_quotient line 174

    Source documentation

    Global extension across the simple-zero divisor of P. The only vanishing hypothesis is the actual numerator order at the zeros, not a pre-existing quotient.

    theorem exists_global_analytic_quotient {f P : ℂ → ℂ} {U : Set ℂ}
        (hU : IsOpen U) (hf : AnalyticOnNhd ℂ f U) (hP : AnalyticOnNhd ℂ P U)
        (k : ℕ) (hzero : ∀ z ∈ U, P z = 0 → deriv P z ≠ 0 ∧
          (k : ℕ∞) ≤ analyticOrderAt f z) :
        ∃ G : ℂ → ℂ, AnalyticOnNhd ℂ G U ∧
          (∀ z ∈ U, f z = P z ^ k * G z) ∧ (∀ z ∉ U, G z = 0) := by
    …
  10. theorem OAI.Nagata.LocalDivision.quotient_nonzero_of_nonzero line 191

    Source documentation

    A nonzero original coefficient stays nonzero after the constructed division.

    theorem quotient_nonzero_of_nonzero {f P G : ℂ → ℂ} {U : Set ℂ} (k : ℕ)
        (hfactor : ∀ z ∈ U, f z = P z ^ k * G z)
        (hf : ∃ z ∈ U, f z ≠ 0) : ∃ z ∈ U, G z ≠ 0 := by
    …
  11. def OAI.Nagata.CoefficientSpaces.sectionCoverMap line 210

    Source documentation

    Literal multiplication by a section on the genuine line-bundle cover.

    def sectionCoverMap {τ δ : ℂˣ} {s : ℤ}
        (P : Nagata.W08.automorphicSections (τ : ℂ) s (δ : ℂ))
        (p : MultiplicativeLineCover ℂ) : MultiplicativeLineCover ℂ :=
    …

    Mentions: OAI.Nagata.W08.automorphicSections

  12. theorem OAI.Nagata.CoefficientSpaces.sectionCoverMap_step line 216

    Source documentation

    Tensor multiplication commutes with the actual period generator.

    theorem sectionCoverMap_step (τ γ δ : ℂˣ) (n s : ℤ)
        (P : Nagata.W08.automorphicSections (τ : ℂ) s (δ : ℂ))
        (p : MultiplicativeLineCover ℂ) :
        sectionCoverMap P (multiplierStep τ γ n p) =
          multiplierStep τ (γ * δ) (n + s) (sectionCoverMap P p) := by
    …

    Mentions: OAI.Nagata.W08.automorphicSections, OAI.Nagata.CoefficientSpaces.sectionCoverMap

  13. theorem OAI.Nagata.CoefficientSpaces.sectionCoverMap_iterate line 231

    Source documentation

    Equivariance holds for every integer period, including inverse transitions.

    theorem sectionCoverMap_iterate (τ γ δ : ℂˣ) (n s k : ℤ)
        (P : Nagata.W08.automorphicSections (τ : ℂ) s (δ : ℂ))
        (p : MultiplicativeLineCover ℂ) :
        sectionCoverMap P (multiplierIterate τ γ n k p) =
          multiplierIterate τ (γ * δ) (n + s) k (sectionCoverMap P p) := by
    …

    Mentions: OAI.Nagata.W08.automorphicSections, OAI.Nagata.CoefficientSpaces.sectionCoverMap

  14. def OAI.Nagata.CoefficientSpaces.sectionQuotientMap line 257

    Source documentation

    The actual globally defined map between the two multiplier quotients.

    def sectionQuotientMap (τ γ δ : ℂˣ) (n s : ℤ)
        (P : Nagata.W08.automorphicSections (τ : ℂ) s (δ : ℂ)) :
        MultiplierQuotient τ γ n → MultiplierQuotient τ (γ * δ) (n + s) :=
    …

    Mentions: OAI.Nagata.W08.automorphicSections

  15. theorem OAI.Nagata.CoefficientSpaces.sectionQuotientMap_mk line 267

    Source documentation

    Evaluation on any genuine lifted fibre is multiplication by the section value.

    theorem sectionQuotientMap_mk (τ γ δ : ℂˣ) (n s : ℤ)
        (P : Nagata.W08.automorphicSections (τ : ℂ) s (δ : ℂ))
        (z : ℂˣ) (t : ℂ) :
        sectionQuotientMap τ γ δ n s P (Quotient.mk _ (z, t)) =
          Quotient.mk _ (z, P.val z * t) := rfl
    …

    Mentions: OAI.Nagata.W08.automorphicSections, OAI.Nagata.CoefficientSpaces.sectionQuotientMap

  16. def OAI.Nagata.FiberCoordinateChange.fibreChart line 283

    Source documentation

    Actual fibre substitution w=P(z)*v over an open base where P is nonzero.

    noncomputable def fibreChart (P : ℂ → ℂ) (U : Set ℂ) (hU : IsOpen U)
        (hP : AnalyticOnNhd ℂ P U) (hne : ∀ z ∈ U, P z ≠ 0) :
        OpenPartialHomeomorph (ℂ × ℂ) (ℂ × ℂ) where
    …
  17. theorem OAI.Nagata.FiberCoordinateChange.fibreChart_analyticAt line 315

    Source documentation

    Analyticity of the actual forward fibre coordinate map.

    theorem fibreChart_analyticAt (P : ℂ → ℂ) (U : Set ℂ) (hU : IsOpen U)
        (hP : AnalyticOnNhd ℂ P U) (hne : ∀ z ∈ U, P z ≠ 0)
        (x : ℂ × ℂ) (hx : x.1 ∈ U) :
        AnalyticAt ℂ (fibreChart P U hU hP hne) x := by
    …

    Mentions: OAI.Nagata.FiberCoordinateChange.fibreChart

  18. theorem OAI.Nagata.FiberCoordinateChange.fibreChart_symm_analyticAt line 324

    Source documentation

    Analyticity of the actual inverse fibre coordinate map.

    theorem fibreChart_symm_analyticAt (P : ℂ → ℂ) (U : Set ℂ) (hU : IsOpen U)
        (hP : AnalyticOnNhd ℂ P U) (hne : ∀ z ∈ U, P z ≠ 0)
        (x : ℂ × ℂ) (hx : x.1 ∈ U) :
        AnalyticAt ℂ (fibreChart P U hU hP hne).symm x := by
    …

    Mentions: OAI.Nagata.FiberCoordinateChange.fibreChart

  19. theorem OAI.Nagata.FiberCoordinateChange.order_preserved_by_fibre_substitution line 334

    Source documentation

    Exactly the multiplicity-preserving transformation in necessary-W: substitute w=P*v and divide the value frame by P^m.

    theorem order_preserved_by_fibre_substitution
        (P : ℂ → ℂ) (U : Set ℂ) (hU : IsOpen U)
        (hP : AnalyticOnNhd ℂ P U) (hne : ∀ z ∈ U, P z ≠ 0)
        (F : (ℂ × ℂ) → ℂ) (x : ℂ × ℂ) (hx : x.1 ∈ U) (m : ℕ) :
        HasAnalyticOrderAtLeast (𝕜 := ℂ)
    …
  20. theorem OAI.Nagata.LocalDivision.quotient_transition_off_zero line 363

    Source documentation

    Cancellation derives the quotient transition wherever the denominator is nonzero.

    theorem quotient_transition_off_zero {T : ℂ → ℂ} {f P G A B : ℂ → ℂ}
        (k : ℕ) (z : ℂ) (hP : P z ≠ 0) (hB : B z ≠ 0)
        (hfz : f z = P z ^ k * G z) (hfT : f (T z) = P (T z) ^ k * G (T z))
        (htf : f (T z) = A z * f z) (htP : P (T z) = B z * P z) :
        G (T z) = (A z / B z ^ k) * G z := by
    …
  21. theorem OAI.Nagata.LocalDivision.quotient_transition_global line 384

    Source documentation

    The actual quotient transition extends over all zeros by continuity and isolated zeros. This closes the local-to-global transition step.

    theorem quotient_transition_global {T : ℂ → ℂ} {f P G A B : ℂ → ℂ}
        {U : Set ℂ} (hU : IsOpen U) (k : ℕ)
        (hP : AnalyticOnNhd ℂ P U) (hPfin : ∀ z ∈ U, analyticOrderAt P z ≠ ⊤)
        (hTU : Set.MapsTo T U U) (hB : ∀ z ∈ U, B z ≠ 0)
        (hfactor : ∀ z ∈ U, f z = P z ^ k * G z)
        (htf : ∀ z ∈ U, f (T z) = A z * f z)
        (htP : ∀ z ∈ U, P (T z) = B z * P z)
        (hleft : ∀ z ∈ U, ContinuousAt (fun w => G (T w)) z)
        (hright : ∀ z ∈ U, ContinuousAt (fun w => (A w / B w ^ k) * G w) z) :
        ∀ z ∈ U, G (T z) = (A z / B z ^ k) * G z := by
    …
  22. def OAI.Nagata.CoefficientSpaces.multiplySection line 410

    Source documentation

    The literal multiplication map restricted to actual automorphic sections.

    noncomputable def multiplySection (τ γ : ℂ) (n : ℤ) (P : ℂ → ℂ) (k : ℕ) :
        Nagata.W08.automorphicSections τ n γ →ₗ[ℂ] (ℂ → ℂ) :=
    …

    Mentions: OAI.Nagata.W08.automorphicSections

  23. theorem OAI.Nagata.CoefficientSpaces.multiplySection_injective line 417

    Source documentation

    No nonzero source section is lost in the positive-index coefficient image. The omitted point contributes no fake section because both representatives are normalized to zero there.

    theorem multiplySection_injective (τ γ : ℂ) (n : ℤ) (P : ℂ → ℂ) (k : ℕ)
        (hP : AnalyticOnNhd ℂ P {z | z ≠ 0})
        (hPfin : ∀ z ≠ 0, analyticOrderAt P z ≠ ⊤) :
        Function.Injective (multiplySection τ γ n P k) := by
    …

    Mentions: OAI.Nagata.CoefficientSpaces.multiplySection

  24. theorem OAI.Nagata.CoefficientSpaces.quotient_multiplier_identity line 441

    Source documentation

    The exact degree and multiplier of a quotient coefficient.

    theorem quotient_multiplier_identity {γ δ z : ℂ} (hδ : δ ≠ 0) (hz : z ≠ 0)
        (n s : ℤ) (k : ℕ) :
        (γ * z ^ (-n)) / (δ * z ^ (-s)) ^ k =
          (γ / δ ^ k) * z ^ (-(n - (k : ℤ) * s)) := by
    …
  25. theorem OAI.Nagata.CoefficientSpaces.exists_automorphic_quotient line 449