Divisibility of the Hurwitz form by the eigendiscriminant

Let ff be a cubic form in four variables, and let its eigenscheme determine a 33-plane in the relevant Grassmannian. The eigenscheme is the scheme defined by the equations fxiλxi\frac{\partial f}{\partial x_i}-\lambda x_i for i=0,,3i=0,\ldots,3; the eigendiscriminant is the homogeneous polynomial that vanishes when this eigenscheme is nonreduced or positive dimensional. The Hurwitz form is the polynomial on Gr(3,P14)\operatorname{Gr}(3,\mathbb{P}^{14}) vanishing on 33-planes that intersect the Veronese tangentially.

Divisibility conjecture. Restricted to the 33-planes coming from eigenschemes, the eigendiscriminant divides the Hurwitz form.

The conjecture compares two discriminantal constructions associated with the Veronese embedding: the eigendiscriminant detects degeneracy of eigenschemes, while the Hurwitz form detects tangential intersection. The source presents this divisibility as an interesting comparison and does not provide evidence of a resolution.

Sources & referencesView supporting material

Primary source

Türkü Özlüm Celik, Francesco Galuppi, Avinash Kulkarni and Miruna-Stefana Sorea, “On the eigenpoints of cubic surfaces”, arXiv:1909.06261 (2020).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.