Heuristics for (ir)reducibility of $p$-rank strata of the moduli space of hyperelliptic curves

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Bouchet, Thomas, Davis, Erik, Groen, Steven R., Porat, Zachary, York, Benjamin
Formato: Preprint
Publicado: 2025
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866916782734835712
author Bouchet, Thomas
Davis, Erik
Groen, Steven R.
Porat, Zachary
York, Benjamin
author_facet Bouchet, Thomas
Davis, Erik
Groen, Steven R.
Porat, Zachary
York, Benjamin
contents Let $\mathcal{H}_g$ denote the moduli space of smooth hyperelliptic curves of genus $g$ in characteristic $p\geq 3$, and let $\mathcal{H}_g^f$ denote the $p$-rank $f$ stratum of $\mathcal{H}_g$ for $0 \leq f \leq g$. Achter and Pries note in their 2011 work that determining the number of irreducible components of $\mathcal{H}_g^f$ would lead to several intriguing corollaries. In this paper, we present a computational approach for estimating the number of irreducible components in various $p$-rank strata. Our strategy involves sampling curves over finite fields and calculating their $p$-ranks. From the data gathered, we conjecture that the non-ordinary locus is geometrically irreducible for all genera $g> 1$. The data also leads us to conjecture that the moduli space $\mathcal{H}^{g-2}_g$ is irreducible and suggests that $\mathcal{H}^f_g$ is irreducible for all $1 \leq f \leq g$. We conclude with a brief discussion on $\mathcal{H}^0_g$.
format Preprint
id arxiv_https___arxiv_org_abs_2506_06457
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Heuristics for (ir)reducibility of $p$-rank strata of the moduli space of hyperelliptic curves
Bouchet, Thomas
Davis, Erik
Groen, Steven R.
Porat, Zachary
York, Benjamin
Algebraic Geometry
Number Theory
14Q05, 14H10, 14G15, 14G17
Let $\mathcal{H}_g$ denote the moduli space of smooth hyperelliptic curves of genus $g$ in characteristic $p\geq 3$, and let $\mathcal{H}_g^f$ denote the $p$-rank $f$ stratum of $\mathcal{H}_g$ for $0 \leq f \leq g$. Achter and Pries note in their 2011 work that determining the number of irreducible components of $\mathcal{H}_g^f$ would lead to several intriguing corollaries. In this paper, we present a computational approach for estimating the number of irreducible components in various $p$-rank strata. Our strategy involves sampling curves over finite fields and calculating their $p$-ranks. From the data gathered, we conjecture that the non-ordinary locus is geometrically irreducible for all genera $g> 1$. The data also leads us to conjecture that the moduli space $\mathcal{H}^{g-2}_g$ is irreducible and suggests that $\mathcal{H}^f_g$ is irreducible for all $1 \leq f \leq g$. We conclude with a brief discussion on $\mathcal{H}^0_g$.
title Heuristics for (ir)reducibility of $p$-rank strata of the moduli space of hyperelliptic curves
topic Algebraic Geometry
Number Theory
14Q05, 14H10, 14G15, 14G17
url https://arxiv.org/abs/2506.06457