English

The Beilinson-Bloch conjecture for some non-isotrivial varieties over global function fields

Number Theory 2026-02-24 v3 Algebraic Geometry

Abstract

The Beilinson--Bloch conjecture is a generalization of the Birch and Swinnerton-Dyer conjecture, which relates the ranks of Chow groups of smooth projective varieties over global fields to the order of vanishing of LL-functions. We prove the conjecture for certain classes of non-isotrivial varieties over Fq(t)\mathbb{F}_q(t), including some cubic threefolds and fivefolds. We deduce the Birch and Swinnerton-Dyer conjecture for their intermediate Jacobians, and use it to establish new cases of the Tate conjecture over finite fields. We also prove further results on the arithmetic of these intermediate Jacobians. To that end, we show that a few classes of varieties over an arbitrary field have motive of abelian type, generalizing previously known examples over the complex numbers.

Keywords

Cite

@article{arxiv.2509.03602,
  title  = {The Beilinson-Bloch conjecture for some non-isotrivial varieties over global function fields},
  author = {Matt Broe},
  journal= {arXiv preprint arXiv:2509.03602},
  year   = {2026}
}

Comments

46 pages. Extended some results on cubic threefolds to cubic fivefolds. Section 3 significantly expanded. Added explicit criterion for existence of Lefschetz pencils in section 5. Minor updates to exposition and typo fixes throughout. All results of previous versions are preserved in their original form. Comments welcome

R2 v1 2026-07-01T05:19:48.668Z