English

Perazzo 3-folds and the weak Lefschetz property

Algebraic Geometry 2023-03-17 v2 Commutative Algebra

Abstract

We deal with Perazzo 3-folds in P4\mathbb P^4, i.e. hypersurfaces X=V(f)P4X=V(f)\subset \mathbb P^4 of degree dd defined by a homogeneous polynomial f(x0,x1,x2,u,v)=p0(u,v)x0+p1(u,v)x1+p2(u,v)x2+g(u,v)f(x_0,x_1,x_2,u,v)=p_0(u,v)x_0+p_1(u,v)x_1+p_2(u,v)x_2+g(u,v), where p0,p1,p2p_0,p_1,p_2 are algebraically dependent but linearly independent forms of degree d1d-1 in u,vu,v, and gg is a form in u,vu,v of degree dd. Perazzo 3-folds have vanishing hessian and, hence, the associated graded artinian Gorenstein algebra AfA_f fails the strong Lefschetz property. In this paper, we determine the maximum and minimum Hilbert function of AfA_f and we prove that if AfA_f has maximal Hilbert function it fails the weak Lefschetz property, while it satisfies the weak Lefschetz property when it has minimum Hilbert function. In addition, we classify all Perazzo 3-folds in P4\mathbb P^4 such that AfA_f has minimum Hilbert function.

Keywords

Cite

@article{arxiv.2206.02723,
  title  = {Perazzo 3-folds and the weak Lefschetz property},
  author = {Luca Fiorindo and Emilia Mezzetti and Rosa M. Miró-Roig},
  journal= {arXiv preprint arXiv:2206.02723},
  year   = {2023}
}

Comments

21 pages; final version to be published in Journal of Algebra