Weak Brill-Noether on Abelian Surfaces

Fuente: arXiv
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Autori principali: Coskun, Izzet, Nuer, Howard, Yoshioka, Kota
Natura: Preprint
Pubblicazione: 2024
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author Coskun, Izzet
Nuer, Howard
Yoshioka, Kota
author_facet Coskun, Izzet
Nuer, Howard
Yoshioka, Kota
contents We study the cohomology of a general stable sheaf on an abelian surface. We say that a moduli space satisfies weak Brill-Noether if the general sheaf has at most one non-zero cohomology group. Let $(X,H)$ be a polarized abelian surface and let $\mathbf{v}=(r,ξ,a)$ be a Mukai vector on $X$ with $\mathbf{v}^2\ge 0$,$r>0$, and $ξ\cdot H>0$. We show that if $ρ(X)=1$ or $ρ(X)=2$ and $X$ contains an elliptic curve, then all the moduli spaces $M_{X,H}(\mathbf{v})$ satisfy weak Brill-Noether. Conversely, if $ρ(X)>2$ or $ρ(X)=2$ and $X$ does not contain an elliptic curve, we show that there are infinitely many moduli spaces $M_{X,H}(\mathbf{v})$ that fail weak Brill-Noether. As a consequence, we classify Chern classes of Ulrich bundles on abelian surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2408_06095
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Weak Brill-Noether on Abelian Surfaces
Coskun, Izzet
Nuer, Howard
Yoshioka, Kota
Algebraic Geometry
Primary 14D20, 14K99. Secondary: 14F06, 14F08
We study the cohomology of a general stable sheaf on an abelian surface. We say that a moduli space satisfies weak Brill-Noether if the general sheaf has at most one non-zero cohomology group. Let $(X,H)$ be a polarized abelian surface and let $\mathbf{v}=(r,ξ,a)$ be a Mukai vector on $X$ with $\mathbf{v}^2\ge 0$,$r>0$, and $ξ\cdot H>0$. We show that if $ρ(X)=1$ or $ρ(X)=2$ and $X$ contains an elliptic curve, then all the moduli spaces $M_{X,H}(\mathbf{v})$ satisfy weak Brill-Noether. Conversely, if $ρ(X)>2$ or $ρ(X)=2$ and $X$ does not contain an elliptic curve, we show that there are infinitely many moduli spaces $M_{X,H}(\mathbf{v})$ that fail weak Brill-Noether. As a consequence, we classify Chern classes of Ulrich bundles on abelian surfaces.
title Weak Brill-Noether on Abelian Surfaces
topic Algebraic Geometry
Primary 14D20, 14K99. Secondary: 14F06, 14F08
url https://arxiv.org/abs/2408.06095