English

Faber--Pandharipande cycle, real multiplication and torsion points

Algebraic Geometry 2025-08-13 v2

Abstract

A result of Green and Griffiths states that for the generic curve CC over C\mathbb{C} of genus g4g \geq 4 with a canonical divisor KK, its Faber--Pandharipande 0-cycle K×K(2g2)KΔK\times K-(2g-2)K_\Delta on C×CC\times C is nontorsion in the Chow group of rational equivalence classes. However, according to a conjecture of Beilinson and Bloch, this Chow cycle vanishes if the curve is defined over a number field. We give a proof of this prediction for Shimura curves which have real multiplication. Our method also works for some other classes curves with partial real multiplication. We also draw a connection between the Faber--Pandharipande 0-cycles and torsion points on curves under the Abel--Jacobi map.

Keywords

Cite

@article{arxiv.2409.08989,
  title  = {Faber--Pandharipande cycle, real multiplication and torsion points},
  author = {Congling Qiu},
  journal= {arXiv preprint arXiv:2409.08989},
  year   = {2025}
}

Comments

Updated from an earlier version, and changed title to reflect the updates