English

Supersingular curves of genus four in characteristic two

Algebraic Geometry 2023-01-31 v1 Number Theory

Abstract

We describe the intersection of the Torelli locus j(M4ct)=J4j(\mathcal{M}_4^{ct}) = \mathcal{J}_4 with Newton and Ekedahl-Oort strata related to the supersingular locus in characteristic two. We show that the locus of supersingular Jacobians S4J4\mathcal{S}_4\cap\mathcal{J}_4 in characteristic two is pure of dimension three. One way to obtain that result uses an analysis of the data of smooth genus four curves and principally polarized abelian fourfolds defined over F2\mathbb{F}_2, and another involves studying the Ekedahl-Oort types and using the indecomposability of some BT1\mathrm{BT}_1 group schemes.

Keywords

Cite

@article{arxiv.2301.12897,
  title  = {Supersingular curves of genus four in characteristic two},
  author = {Dušan Dragutinović},
  journal= {arXiv preprint arXiv:2301.12897},
  year   = {2023}
}