Nonemptiness and smoothness of twisted Brill-Noether loci



Hitching, George H, Hoff, Michael and Newstead, Peter E ORCID: 0000-0002-2498-7992
(2020) Nonemptiness and smoothness of twisted Brill-Noether loci. Annali di Matematica Pura ed Applicata, 200 (2). pp. 685-709.

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Abstract

Let $V$ be a vector bundle over a smooth curve $C$. In this paper, we study twisted Brill--Noether loci parametrising stable bundles $E$ of rank $n$ and degree $e$ with the property that $h^0 (C, V \otimes E) \ge k$. We prove that, under conditions similar to those of Teixidor i Bigas and of Mercat, the Brill-Noether loci are nonempty, and in many cases have a component which is generically smooth and of the expected dimension. Along the way, we prove the irreducibility of certain components of both twisted and "nontwisted" Brill--Noether loci. We describe the tangent cones to the twisted Brill-Noether loci. We end with an example of a general bundle over a general curve having positive-dimensional twisted Brill--Noether loci with negative expected dimension.

Item Type: Article
Additional Information: 23 pages, typos corrected, new section "Tangent cones to twisted Brill-Noether loci"
Uncontrolled Keywords: math.AG, math.AG, 14H60 (14H51)
Depositing User: Symplectic Admin
Date Deposited: 07 Jul 2020 07:56
Last Modified: 18 Jan 2023 23:46
DOI: 10.1007/s10231-020-01009-x
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3093019