Published December 2024 | Version Published
Journal Article

Abelian Covers of ℙ¹ of p-Ordinary Ekedahl–Oort Type

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of California, Irvine

Abstract

Given a family of abelian covers ℙ¹ and a prime p of good reduction, by considering the associated Deligne–Mostow Shimura variety, we obtain non-trivial bounds for the Ekedahl–Oort types, and the Newton polygons, at prime p for the curves in the family. In this paper, we investigate whether such bounds are sharp. In particular, we prove sharpness when the number of branching points is at most five and p sufficiently large. Our result is a generalization under stricter assumptions of [2, Theorem 6.1] by Bouw, which proves the analogous statement for the p-rank, and it relies on the notion of Hasse–Witt triple introduced by Moonen in [12].

Copyright and License

© The Author(s) 2024. Published by Oxford University Press. All rights reserved.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/pages/standard-publication-reuse-rights).

Acknowledgement

We would like to thank Rachel Pries for many helpful discussions that have motivated the pursuit of this problem.

Communicated by Prof. Enrico Arbarello.

Funding

E.M. is partially supported by NSF grant DMS-22-00694.

Additional details

Related works

Is new version of
Discussion Paper: arXiv:2303.13350 (arXiv)

Funding

National Science Foundation
DMS-22-00694

Dates

Accepted
2024-09-13
Accepted
Available
2024-10-31
Published

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Publication Status
Published