OAI/AlgebraicGeometry/PlaneCurves/TaylorMultiplicity.lean

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29 declarations, 0 contain sorry, 0 declared as axioms

Translation, Taylor coefficients, and ordinary multiplicity

  1. theorem OAI.Nagata.AffineMultiplicity.cancel_nonmember_maximal_power line 21
  2. theorem OAI.Nagata.AffineMultiplicity.orderAtLeast_cancel_nonvanishing line 40
  3. def OAI.Nagata.AffineMultiplicity.translateHom line 60

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:49 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateHom@path.

  4. theorem OAI.Nagata.AffineMultiplicity.translateHom_C line 63

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:53 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateHom_C@path.

  5. theorem OAI.Nagata.AffineMultiplicity.translateHom_X line 67

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:57 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateHom_X@path.

  6. theorem OAI.Nagata.AffineMultiplicity.translateHom_neg_comp line 71

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:61 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateHom_neg_comp@path.

  7. theorem OAI.Nagata.AffineMultiplicity.translateHom_comp_neg line 77

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:67 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateHom_comp_neg@path.

  8. def OAI.Nagata.AffineMultiplicity.translateEquiv line 81

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:71 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateEquiv@path.

  9. theorem OAI.Nagata.AffineMultiplicity.translateEquiv_apply line 87

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:77 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translateEquiv_apply@path.

  10. theorem OAI.Nagata.AffineMultiplicity.eval_zero_translate line 90
  11. theorem OAI.Nagata.AffineMultiplicity.eval_translate line 111

    Source documentation

    Actual polynomial evaluation intertwines coordinate translation with translation of the input point, at every point, not only at the origin.

    theorem eval_translate (p x : σ → R) (f : MvPolynomial σ R) :
        MvPolynomial.eval x (translateHom p f) = MvPolynomial.eval (x + p) f := by
    …
  12. theorem OAI.Nagata.AffineMultiplicity.pointIdeal_zero_eq_idealOfVars line 134
  13. theorem OAI.Nagata.AffineMultiplicity.orderAtLeast_iff_taylor_coeff line 145

    Source documentation

    Vanishing order at p is exactly vanishing of every coefficient below total degree m after the explicit translation X ↦ X+p.

    theorem orderAtLeast_iff_taylor_coeff (p : σ → R) (m : ℕ) (f : MvPolynomial σ R) :
        orderAtLeast p m f ↔
          ∀ a : σ →₀ ℕ, Finsupp.degree a < m → (translateHom p f).coeff a = 0 := by
    …
  14. theorem OAI.Nagata.AffineMultiplicity.translate_ne_zero line 173

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:80 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translate_ne_zero@path.

  15. theorem OAI.Nagata.AffineMultiplicity.translated_support_nonempty line 180

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:87 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.translated_support_nonempty@path.

  16. theorem OAI.Nagata.AffineMultiplicity.translated_support_finite line 184
  17. def OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity line 189

    Source documentation

    The ordinary multiplicity is a finite minimum of genuine Taylor degrees.

    Distinct definitions of this name: ComparatorChallenges/Nagata.lean:92 (different declaration text). Qualify references as OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity@path.

    noncomputable def ordinaryMultiplicity (p : σ → R) (f : MvPolynomial σ R)
        (hf : f ≠ 0) : ℕ :=
    …
  18. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_attained line 194

    Source documentation

    The minimum is attained by an actual nonzero coefficient.

    theorem ordinaryMultiplicity_attained (p : σ → R) (f : MvPolynomial σ R)
        (hf : f ≠ 0) :
        ∃ a : σ →₀ ℕ, (translateHom p f).coeff a ≠ 0 ∧
          ordinaryMultiplicity p f hf = Finsupp.degree a := by
    …
  19. theorem OAI.Nagata.AffineMultiplicity.orderAtLeast_iff_le_ordinaryMultiplicity line 203

    Source documentation

    The baseline lower-bound predicate agrees with the actual numeric order.

    theorem orderAtLeast_iff_le_ordinaryMultiplicity
        (p : σ → R) (m : ℕ) (f : MvPolynomial σ R) (hf : f ≠ 0) :
        orderAtLeast p m f ↔ m ≤ ordinaryMultiplicity p f hf := by
    …
  20. theorem OAI.Nagata.AffineMultiplicity.orderAtLeast_ordinaryMultiplicity line 214
  21. theorem OAI.Nagata.AffineMultiplicity.not_orderAtLeast_succ_ordinaryMultiplicity line 218
  22. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_equiv line 225

    Source documentation

    Any actual evaluation-compatible polynomial-ring isomorphism preserves the finite minimum; its nonzero and coordinate hypotheses are explicit.

    theorem ordinaryMultiplicity_equiv {τ : Type*}
        (p : σ → R) (q : τ → R)
        (e : MvPolynomial σ R ≃+* MvPolynomial τ R)
        (he : ∀ f, MvPolynomial.eval q (e f) = MvPolynomial.eval p f)
        (f : MvPolynomial σ R) (hf : f ≠ 0) (hef : e f ≠ 0) :
        ordinaryMultiplicity q (e f) hef = ordinaryMultiplicity p f hf := by
    …
  23. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_translate line 241

    Source documentation

    Actual translation preserves numerical multiplicity when its center is moved to the origin. The coordinate isomorphism is explicitly constructed.

    theorem ordinaryMultiplicity_translate (p : σ → R) (f : MvPolynomial σ R)
        (hf : f ≠ 0) :
        ordinaryMultiplicity (0 : σ → R) (translateHom p f) (translate_ne_zero p f hf) =
          ordinaryMultiplicity p f hf :=
    …
  24. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_unit_mul line 248
  25. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_mul_lower_bound line 260
  26. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_pow_lower_bound line 268
  27. theorem OAI.Nagata.AffineMultiplicity.ordinaryMultiplicity_nonvanishing_mul line 280

    Source documentation

    Nonvanishing multipliers are units in the local ring and leave the actual minimum unchanged, even when they are not units in the polynomial ring.

    theorem ordinaryMultiplicity_nonvanishing_mul (p : σ → F) (f g : MvPolynomial σ F)
        (hf : f ≠ 0) (hgf : g * f ≠ 0) (hg : MvPolynomial.eval p g ≠ 0) :
        ordinaryMultiplicity p (g * f) hgf = ordinaryMultiplicity p f hf := by
    …
  28. theorem OAI.Nagata.AffineMultiplicity.pointIdeal_finTwo_zero line 303
  29. theorem OAI.Nagata.AffineMultiplicity.orderAtLeast_finTwo_iff_taylor_coeff line 324

    Source documentation

    Exact ordinary multiplicity criterion for a plane polynomial, including mixed Taylor coefficients and order zero.

    theorem orderAtLeast_finTwo_iff_taylor_coeff
        (p : Fin 2 → R) (m : ℕ) (f : MvPolynomial (Fin 2) R) :
        orderAtLeast p m f ↔ ∀ ell b : ℕ, ell + b < m →
          (translateHom p f).coeff (Nagata.Workers.W30.exponentPair ell b) = 0 := by
    …

    Mentions: OAI.Nagata.Workers.W30.exponentPair