Modified Bronowski conjecture on identifiability and secant-variety degree

Let XPNX\subset\mathbb{P}^N be an irreducible and non-degenerate variety. Let Sech(X)\mathbb{S}ec_h(X) denote the Zariski closure of the union of the (h1)(h-1)-planes spanned by hh points of XX, and set

ch=codimPN(Sech(X)).c_h=\operatorname{codim}_{\mathbb{P}^N}(\mathbb{S}ec_h(X)).

A variety of minimal degree has the smallest possible degree for its codimension.

Modified Bronowski conjecture. If a general (h1)(h-1)-tangential projection of XX is birational and its image is a variety of minimal degree, then XX is hh-identifiable and

degSech(X)=(h+chh).\deg\mathbb{S}ec_h(X)=\binom{h+c_h}{h}.

The degree in the conclusion is the smallest possible degree of the hh-secant variety. The conjecture was proposed as a modification of Bronowski's conjecture and is implied by the original conjecture, but the paper gives counterexamples to both statements.

Sources & referencesView supporting material

Primary source

Alex Massarenti and Massimiliano Mella, “Bronowski's conjecture and the identifiability of projective varieties”, arXiv:2210.13524 (2024).

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.