English

On the duals of smooth projective complex hypersurfaces

Algebraic Geometry 2023-10-17 v3

Abstract

We show first that a generic hypersurface VV of degree d3d\geq 3 in the complex projective space Pn \mathbb{P}^n of dimension n3n \geq 3 has at least one hyperplane section VHV \cap H containing exactly nn ordinary double points, alias A1A_1 singularities, in general position, and no other singularities. Equivalently, the dual hypersurface VV^{\vee} has at least one normal crossing singularity of multiplicity nn. Using this result, we show that the dual of any smooth hypersurface with n,d3n,d \geq 3 has at least a very singular point qq, in particular a point qq of multiplicity n\geq n.

Keywords

Cite

@article{arxiv.2301.06952,
  title  = {On the duals of smooth projective complex hypersurfaces},
  author = {Alexandru Dimca and Giovanna Ilardi},
  journal= {arXiv preprint arXiv:2301.06952},
  year   = {2023}
}

Comments

v3. Some details are added to the proof of the main result. This version will be published in Publicacions Matem\`atiques

R2 v1 2026-06-28T08:13:32.875Z