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A uniform quantitative Manin–Mumford theorem for curves over function fields

  • Nicole Looper EMAIL logo , Joseph Silverman and Robert Wilms
Published/Copyright: August 21, 2025

Abstract

We prove that any smooth projective geometrically connected non-isotrivial curve of genus g 2 over a one-dimensional function field of any characteristic has at most 16 g 2 + 32 g + 124 torsion points for any Abel–Jacobi embedding of the curve into its Jacobian. The proof uses Zhang’s admissible pairing on curves, the arithmetic Hodge index theorem over function fields, and the metrized graph analogue of Elkies’ lower bound for the Green function. More generally, we prove an explicit Bogomolov-type result bounding the number of geometric points of small Néron–Tate height on the curve embedded into its Jacobian.

Award Identifier / Grant number: DMS-1803021

Funding source: Simons Foundation

Award Identifier / Grant number: 712332

Award Identifier / Grant number: 200020_184623

Funding statement: The first author was supported by NSF grant DMS-1803021. The second author was partially supported by Simons Collaboration Grant #712332. The third author was supported by the Swiss National Science Foundation grant “Diophantine Equations: Special Points, Integrality, and Beyond” (nº 200020_184623).

Acknowledgements

The authors would like to thank Matt Baker, Alex Carney, Robin de Jong, Xander Faber, Myrto Mavraki, and Lucia Mocz for their helpful conversations and useful insights on the admissible pairing. We also thank Jiawei Yu for pointing out an improvement in the bound for 𝜖 in Theorem 1.3, as well as the editor for the suggestion of adding Corollary 1.2. We thank the anonymous referees for their very careful reading and useful comments on two drafts of this paper.

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Received: 2022-09-06
Revised: 2024-09-14
Published Online: 2025-08-21
Published in Print: 2025-11-01

© 2025 Walter de Gruyter GmbH, Berlin/Boston

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