Linear stability and rank two Clifford indices of algebraic curves with applications

Fuente: arXiv
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Main Authors: Bajravani, Ali, Ortega, Angela
Format: Preprint
Published: 2025
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author Bajravani, Ali
Ortega, Angela
author_facet Bajravani, Ali
Ortega, Angela
contents We prove that any vector bundle computing the rank-two Clifford index of a smooth projective algebraic curve is linearly semistable. We also identify conditions under which such bundles become linearly stable, thereby addressing a question posed by A. Castorena, G. H. Hitching and E. Luna in the rank-two case. Furthermore, we demostrate that in certain special cases, this property is equivalent to the (semi)stability of the associated Lazarsfeld-Mukai bundles. This yields a positive answer, in specific cases, to a generalized version of a conjecture proposed by Mistretta and Stoppino. We also study the moduli space $S_0(n,d,5)$ of generated $α$-stable coherent systems of type $(n,d,5)$ for small values of $α$ and $n=2,3$. We show that a general element of an irreducible component of $X \subseteq S_0(2,d,5)$ or $X \subseteq S_0(3,d,5)$ is linearly stable whenever $2δ_2 \leq d \leq \frac{3g}{2}$. As an application of this, we prove that Butler's conjecture holds non-trivially for coherent systems of type $(2,d,5)$ within the given range for $d$.
format Preprint
id arxiv_https___arxiv_org_abs_2509_06149
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear stability and rank two Clifford indices of algebraic curves with applications
Bajravani, Ali
Ortega, Angela
Algebraic Geometry
14H45, 14H51, 14H60
We prove that any vector bundle computing the rank-two Clifford index of a smooth projective algebraic curve is linearly semistable. We also identify conditions under which such bundles become linearly stable, thereby addressing a question posed by A. Castorena, G. H. Hitching and E. Luna in the rank-two case. Furthermore, we demostrate that in certain special cases, this property is equivalent to the (semi)stability of the associated Lazarsfeld-Mukai bundles. This yields a positive answer, in specific cases, to a generalized version of a conjecture proposed by Mistretta and Stoppino. We also study the moduli space $S_0(n,d,5)$ of generated $α$-stable coherent systems of type $(n,d,5)$ for small values of $α$ and $n=2,3$. We show that a general element of an irreducible component of $X \subseteq S_0(2,d,5)$ or $X \subseteq S_0(3,d,5)$ is linearly stable whenever $2δ_2 \leq d \leq \frac{3g}{2}$. As an application of this, we prove that Butler's conjecture holds non-trivially for coherent systems of type $(2,d,5)$ within the given range for $d$.
title Linear stability and rank two Clifford indices of algebraic curves with applications
topic Algebraic Geometry
14H45, 14H51, 14H60
url https://arxiv.org/abs/2509.06149