Nonzero Euler minors in smooth generic-plane families. The order is exactly d²−1, and the smooth-point argument constructs the geometric irreducibility needed by the characteristic-zero closed-form theorem.
theorem
CCDN.exists_positioned_genericPlane_euler_minor_charZero
{K : Type u_1}
{σ : Type u_2}
[Field K]
[CharZero K]
[IsAlgClosed K]
[Finite σ]
(k : ℕ)
(f : MvPolynomial (Option σ) K)
(hf : Irreducible f)
(hd : f.totalDegree = k + 2)
:
∃ (a : Option σ → K) (b : Option σ → K) (hb : b none ≠ 0),
(MvPolynomial.eval b) ((MvPolynomial.homogeneousComponent f.totalDegree) f) ≠ 0 ∧ (eulerClosedFormCoefficientMatrix k
(genericPlanePolynomial (normalizedHypersurfaceCoordinates a b hb f))).HasNonzeroMinor
((k + 2) ^ 2 - 1)
Over an algebraically closed field of characteristic zero, every irreducible polynomial f of
degree k + 2 admits an affine coordinate change, given by a and b with b none ≠ 0 and the
top-degree form of f nonvanishing at b, after which the Euler closed-form coefficient matrix of
the generic plane section has a nonzero minor of order (k + 2) ^ 2 - 1.