OAI/AlgebraicGeometry/CommutingDerivations/CoordinatePartials.lean
7 declarations, 0 contain sorry, 0 declared as axioms
The actual polynomial coordinate partials: commuting, locally nilpotent, linearly independent over the polynomial ring, and with exact constant common kernel in characteristic zero. No localization equivalence is assumed here.
- theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partials_commuteline 17 - theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partial_iterate_eq_zeroline 29Source documentation
Vanishing of all coefficients at exponent at least n implies annihilation by the nth partial iterate. This works over every commutative ring.
theorem coordinate_partial_iterate_eq_zero (i : σ) (n : ℕ) (p : MvPolynomial σ B) (hp : ∀ m : σ →₀ ℕ, n ≤ m i → p.coeff m = 0) : (pderiv i : MvPolynomial σ B → MvPolynomial σ B)^[n] p = 0 := by …Mentions: OAI.AbhyankarSathaye.p
- theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partial_nilpotence_boundline 50Source documentation
An explicit pointwise bound: one more than the largest exponent of i among the finitely many supported monomials.
theorem coordinate_partial_nilpotence_bound (i : σ) (p : MvPolynomial σ B) : (pderiv i : MvPolynomial σ B → MvPolynomial σ B)^[ p.support.sup (fun m => m i) + 1] p = 0 := by …Mentions: OAI.AbhyankarSathaye.p
- theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partial_locallyNilpotentline 62 - theorem
OAI.AbhyankarSathaye.CommutingDerivations.coefficient_eq_zero_of_all_partials_zeroline 68Source documentation
Exact coefficient consequence of the common-kernel condition.
theorem coefficient_eq_zero_of_all_partials_zero [IsDomain B] [CharZero B] (p : MvPolynomial σ B) (hp : ∀ i, pderiv i p = 0) (m : σ →₀ ℕ) (hm : m ≠ 0) : p.coeff m = 0 := by …Mentions: OAI.AbhyankarSathaye.p
- theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partials_common_kernelline 92Source documentation
The common kernel is literally the coefficient ring, with witness equal to the constant coefficient. In particular this applies to Laurent coefficients over C, once that coefficient algebra's domain and characteristic are installed.
theorem coordinate_partials_common_kernel [IsDomain B] [CharZero B] (p : MvPolynomial σ B) : (∀ i, pderiv i p = 0) ↔ ∃ b : B, p = C b := by …Mentions: OAI.AbhyankarSathaye.p
- theorem
OAI.AbhyankarSathaye.CommutingDerivations.coordinate_partials_linearIndependentline 107