Computing Crystalline Cohomology and p-Divisible Groups for Curves over Finite Fields
Number Theory
2026-01-21 v1 Algebraic Geometry
Abstract
Let be a smooth projective curve over a finite field of characteristic . We describe and implement a practical algorithm for computing the -divisible group via computing its Dieudonn\'{e} module, or equivalently computing the Frobenius and Verschiebung operators on the first crystalline cohomology of . We build on Tuitman's -adic point counting algorithm, which computes the rigid cohomology of and requires a ``nice'' lift of to be provided.
Cite
@article{arxiv.2601.14006,
title = {Computing Crystalline Cohomology and p-Divisible Groups for Curves over Finite Fields},
author = {Jeremy Booher},
journal= {arXiv preprint arXiv:2601.14006},
year = {2026}
}
Comments
20 pages, implementation at https://github.com/jeremybooher/crystallinecohomology