English

Algebraic surfaces as Hadamard products of curves

Algebraic Geometry 2026-03-30 v2

Abstract

We study projective surfaces in P3\mathbb{P}^3 which can be written as Hadamard product of two curves. We show that quadratic surfaces which are Hadamard product of two lines are smooth and tangent to all coordinate planes, and such tangency points uniquely identify the quadric. The variety of such quadratic surfaces corresponds to the Zariski closure of the space of symmetric matrices whose inverse has null diagonal. For higher-degree surfaces which are Hadamard product of a line and a curve we show that the intersection with the coordinate planes is always non-transversal.

Keywords

Cite

@article{arxiv.2502.18813,
  title  = {Algebraic surfaces as Hadamard products of curves},
  author = {Dario Antolini and Edoardo Ballico and Alessandro Oneto},
  journal= {arXiv preprint arXiv:2502.18813},
  year   = {2026}
}

Comments

8 pages. Published in Journal of Algebra