English

Asymptotic Betti bounds for hypersurfaces in a singular variety

Algebraic Geometry 2026-01-29 v1

Abstract

We show that for any degree dd hypersurface YXY \subset X in a possibly singular projective variety XPNX \subset \mathbf{P}^N, the total Betti number of YY is bounded by 3deg(X)dn+Cdn13\text{deg}(X)\cdot d^n + C\cdot d^{n-1} for some explicit constant C>0C > 0 independent of dd and YY. When XX is a local complete intersection, the bound improves to deg(X)dn+Cdn1\text{deg}(X)\cdot d^n + C\cdot d^{n-1}. In this case, the bound is asymptotically sharp. Similar bounds are also established for general constructible sheaves.

Keywords

Cite

@article{arxiv.2601.20179,
  title  = {Asymptotic Betti bounds for hypersurfaces in a singular variety},
  author = {Xuanyu Pan and Dingxin Zhang and Xiping Zhang},
  journal= {arXiv preprint arXiv:2601.20179},
  year   = {2026}
}