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Related papers: Maximal Brill-Noether loci via K3 surfaces

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We describe Baily-Borel, toroidal, and geometric -- using the KSBA stable pairs -- compactifications of some moduli spaces of K3 surfaces with a nonsymplectic automorphism of order $3$ and $4$ for which the fixed locus of the automorphism…

Algebraic Geometry · Mathematics 2025-02-12 Valery Alexeev , Anand Deopurkar , Changho Han

By work of Looijenga and others, one has a good understanding of the relationship between GIT and Baily-Borel compactifications for the moduli spaces of degree 2 K3 surfaces, cubic fourfolds, and a few other related examples. The…

Algebraic Geometry · Mathematics 2019-08-15 Radu Laza , Kieran G. O'Grady

We develop a theory of twistor spaces for supersingular K3 surfaces, extending the analogy between supersingular K3 surfaces and complex analytic K3 surfaces. Our twistor spaces are obtained as relative moduli spaces of twisted sheaves on…

Algebraic Geometry · Mathematics 2019-02-12 Daniel Bragg , Max Lieblich

Brill-Noether theory studies the existence and deformations of curves in projective spaces; its basic object of study is $\mathcal{W}^r_{d,g}$, the moduli space of smooth genus $g$ curves with a choice of degree $d$ line bundle having at…

Algebraic Geometry · Mathematics 2013-11-25 Nathan Pflueger

In the moduli space of polarized varieties the same unpolarized variety can occur multiple times However, for K3 surfaces, compact hyperk\"ahler manifolds, and abelian varieties the number is finite. This may be viewed as a consequence of…

Algebraic Geometry · Mathematics 2019-08-20 Daniel Huybrechts

We prove existence and unicity of slope stable vector bundles on a general polarized hyperk\"ahler (HK) variety of type $K3^{[n]}$ with certain discrete invariants, provided the rank and the first two Chern classes of the vector bundle…

Algebraic Geometry · Mathematics 2023-10-17 Kieran Gregory O'Grady

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…

Algebraic Geometry · Mathematics 2024-08-13 Izzet Coskun , Howard Nuer , Kota Yoshioka

We study rank 3 stable bundles E on P^3 as extensions of a line bundle B on a smooth surface S in P^3 by the direct sum of three copies of O_{P^3}(-\nu). In most cases, S (the dependency locus of three sections of E(\nu)) lies in the…

Algebraic Geometry · Mathematics 2007-05-23 Al Vitter

We prove formulas for the rational Chow motives of moduli spaces of semistable vector bundles and Higgs bundles of rank 3 and coprime degree on a smooth projective curve. Our approach involves identifying criteria to lift identities in (a…

Algebraic Geometry · Mathematics 2021-12-21 Lie Fu , Victoria Hoskins , Simon Pepin Lehalleur

In this paper, we study maps from reducible curves $f : C \cup_\Gamma D \to \mathbb{P}^r$. We restrict our attention to two cases: first, when $f|_D$ factors through a hyperplane $H$ and $f|_C$ is transverse to $H$; and second, when $r =…

Algebraic Geometry · Mathematics 2018-09-20 Eric Larson

We compute the Euler characteristic of the structure sheaf of the Brill-Noether locus of linear series with special vanishing at up to two marked points. When the Brill-Noether number $\rho$ is zero, we recover the Castelnuovo formula for…

Algebraic Geometry · Mathematics 2021-02-05 Dave Anderson , Linda Chen , Nicola Tarasca

We prove a generalization of the Brill-Noether theorem for the variety of special divisors $W^r_d(C)$ on a general curve $C$ of prescribed gonality. Our main theorem gives a closed formula for the dimension of $W^r_d(C)$. We build on…

Algebraic Geometry · Mathematics 2022-03-01 David Jensen , Dhruv Ranganathan

We prove two results. First, we establish that the normal bundle of any smooth curve of genus 7 having maximal Clifford index is stable. Note that 7 is the smallest genus for which such a result could possibly hold. We then show that rank…

Algebraic Geometry · Mathematics 2014-10-06 Marian Aprodu , Gavril Farkas , Angela Ortega

Let C be a projective smooth curve of genus g> 1. Let E be a vector bundle of rank r on C. For each integer r'<r, associate to E the invariant s_{r'}(E)=r'deg(E)-rdeg(E') where E'is a subbundle of E of rank r' and maximal degree. For every…

alg-geom · Mathematics 2007-05-23 B. Russo , M. Teixidor i Bigas

We study the geometry of exceptional loci of birational contractions of hyper-K\"ahler fourfolds that are of K3$^{[2]}$-type. These loci are conic bundles over K3 surfaces and we determine their classes in the Brauer group. For this we use…

Algebraic Geometry · Mathematics 2022-12-12 Bert van Geemen , Grzegorz Kapustka

Motivated by a problem originating in string theory, we study elliptic fibrations on K3 surfaces with large Picard number modulo isomorphism. We give methods to determine upper bounds for the number of inequivalent K3 surfaces sharing the…

Algebraic Geometry · Mathematics 2013-12-17 Andreas P. Braun , Yusuke Kimura , Taizan Watari

Let X be a smooth projective complex variety, and L a line bundle on X . We say that the linear system |L| has maximal variation if its elements have the maximum number dim|L| of moduli. We discuss some cases where this situation is…

Algebraic Geometry · Mathematics 2026-01-21 Arnaud Beauville

We study the projective models of complex K3 surfaces polarized by a line bundle L such that all smooth curves in |L| have non-general Clifford index. Such models are in a natural way contained in rational normal scrolls. We use this study…

Algebraic Geometry · Mathematics 2007-05-23 Trygve Johnsen , Andreas Leopold Knutsen

Given the Prym variety of an \'etale double cover one can define analogues of the classical Brill-Noether loci on Jacobians of curves. Recent work by Lahoz and Naranjo shows that the Brill-Noether locus $V^2$ completely determines the…

Algebraic Geometry · Mathematics 2017-11-15 Andreas Höring

In this paper, we compute the cohomology class of certain "special maximal-rank loci" originally defined by Aprodu and Farkas. By showing that such classes are nonzero, we are able to verify the non-emptiness portion of the Strong Maximal…

Algebraic Geometry · Mathematics 2021-01-20 Ethan Cotterill , Adrián Alonso Gonzalo , Naizhen Zhang