English

Semi-regular varieties and variational Hodge conjecture

Algebraic Geometry 2016-12-05 v1

Abstract

We know that semi-regular sub-varieties satisfy the variational Hodge conjecture i.e., given a family of smooth projective varieties π:XB\pi:\mathcal{X} \to B, a special fiber Xo\mathcal{X}_o and a semi-regular subvariety ZXoZ \subset \mathcal{X}_o, the cohomology class corresponding to ZZ remains a Hodge class (as Xo\mathcal{X}_o deforms along BB) if and only if ZZ remains an algebraic cycle. In this article, we investigate examples of such sub-varieties. In particular, we prove that any smooth projective variety ZZ of dimension nn is a semi-regular sub-variety of a smooth projective hypersurface in P2n+1\mathbb{P}^{2n+1} of large enough degree.

Keywords

Cite

@article{arxiv.1612.00754,
  title  = {Semi-regular varieties and variational Hodge conjecture},
  author = {Ananyo Dan and Inder Kaur},
  journal= {arXiv preprint arXiv:1612.00754},
  year   = {2016}
}

Comments

5 pages, published at Comptes rendus - Math\'ematique, 2016

R2 v1 2026-06-22T17:11:55.833Z