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Related papers: Tropical Methods in Hurwitz-Brill-Noether Theory

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We study properties of the tropical double Hurwitz loci defined by Bertram, Cavalieri and Markwig. We show that all such loci are connected in codimension one. If we mark preimages of simple ramification points, then for a generic choice of…

Algebraic Geometry · Mathematics 2015-12-02 Simon Hampe

We construct a space classifying divisor classes of a fixed degree on all tropical curves of a fixed combinatorial type and show that the function taking a divisor class to its rank is upper semicontinuous. We extend the definition of the…

Algebraic Geometry · Mathematics 2014-04-02 Yoav Len

We first prove a generalized Brill-Noether theorem for linear series with prescribed multivanishing sequences on smooth curves. We then apply this theorem to prove that spaces of limit linear series have the expected dimension for a certain…

Algebraic Geometry · Mathematics 2014-10-22 Brian Osserman

Hurwitz spaces are moduli of isotopy classes of covers. A specific space is formed from a finite group G and C, r of its conjugacy classes and an equivalence relation \dagger. Components, interpret as a braid orbits on Nielsen classes.…

Algebraic Geometry · Mathematics 2025-09-12 Michael D. Fried

We introduce stable tropical curves and use these to count covers of the $p$-adic projective line of fixed degree and ramification types by Mumford curves in terms of tropical Hurwitz numbers. Our counts depend on the branch loci of the…

Algebraic Geometry · Mathematics 2008-06-05 Patrick Erik Bradley

Under the assumption that the adjusted Brill-Noether number $\widetilde{\rho}$ is at least $-g$, we prove that the Brill-Noether loci in $\mathcal{M}_{g,n}$ of pointed curves carrying pencils with prescribed ramification at the marked…

Algebraic Geometry · Mathematics 2026-02-17 Andreas Leopold Knutsen , Sara Torelli

In this paper we deal with Brill-Noether theory for higher-rank sheaves on a polarized nodal reducible curve $(C,\underline{w})$ following the ideas of [arXiv:alg-geom/9511003v1]. We study the Brill-Noether loci of $\underline{w}$-stable…

Algebraic Geometry · Mathematics 2022-04-29 Sonia Brivio , Filippo F. Favale

We define the dimension 2g-1 Faber-Hurwitz Chow/homology classes on the moduli space of curves, parametrizing curves expressible as branched covers of P^1 with given ramification over infinity and sufficiently many fixed ramification points…

Algebraic Geometry · Mathematics 2007-05-23 Ian P. Goulden , David M. Jackson , Ravi Vakil

We develop a novel approach to the Brill-Noether theory of curves endowed with a degree k cover of the projective line via Bridgeland stability conditions on elliptic K3 surfaces. We first develop the Brill-Noether theory on elliptic K3…

Algebraic Geometry · Mathematics 2025-06-24 Gavril Farkas , Soheyla Feyzbakhsh , Andrés Rojas

We investigate the Brill-Noether theory of rank-two, degree-$d$ stable vector bundles of speciality $3$ on a general $\nu$-gonal curve of genus $g$, $3 \leq \nu < \lfloor \frac{g+3}{2} \rfloor$. Our approach leverages universal extension…

Algebraic Geometry · Mathematics 2026-02-24 Youngook Choi , Flamino Flamini , Seonja Kim

We study rational double Hurwitz cycles, i.e. loci of marked rational stable curves admitting a map to the projective line with assigned ramification profiles over two fixed branch points. Generalizing the phenomenon observed for double…

Algebraic Geometry · Mathematics 2013-05-21 Aaron Bertram , Renzo Cavalieri , Hannah Markwig

Given a curve $C$ that is a degree $k$ cover $C \to \mathbb{P}^1$ totally ramified at two points $p$ and $q$, we can seek to understand the space of degree $d$ line bundles on $C$ with prescribed ramification at $p$ and $q$. The…

Algebraic Geometry · Mathematics 2026-04-30 Daksh Aggarwal

We develop a theory of Brill-Noether divisors on the moduli space of stable spin curves of genus g, and compute the classes of these loci. A spin Brill-Noether cycle is defined in terms of the relative position of the spin structure with…

Algebraic Geometry · Mathematics 2010-05-07 Gavril Farkas

We propose a generalization of tropical curves by dropping the rationality and integrality requirements while preserving the balancing condition. An interpretation of such curves as critical points of a certain quadratic functional allows…

Algebraic Geometry · Mathematics 2018-12-04 Sergei Lanzat , Michael Polyak

For a projective variety X, a line bundle L on X and r a natural number we consider the r-th Brill-Noether locus W^r(L,X):={\eta\in Pic^0(X)|h^0(L+\eta)\geq r+1}: we describe its natural scheme structure and compute the Zariski tangent…

Algebraic Geometry · Mathematics 2012-10-09 Margarida Mendes Lopes , Rita Pardini , Gian Pietro Pirola

Let $C$ be a curve of genus $g$. A fundamental problem in the theory of algebraic curves is to understand maps $C \to \mathbb{P}^r$ of specified degree $d$. When $C$ is general, the moduli space of such maps is well-understood by the main…

Algebraic Geometry · Mathematics 2025-01-08 Eric Larson , Hannah Larson , Isabel Vogt

We determine the splitting (isomorphism) type of the normal bundle of a generic genus-0 curve with 1 or 2 components in any projective space, as well as the (sometimes nontrivial) way the bundle deforms locally with a general deformation of…

Algebraic Geometry · Mathematics 2007-05-23 Ziv Ran

In this paper, we define tropical analogues of real Hurwitz numbers, i.e. numbers of covers of surfaces with compatible involutions satisfying prescribed ramification properties. We prove a correspondence theorem stating the equality of the…

Algebraic Geometry · Mathematics 2015-08-26 Hannah Markwig , Johannes Rau

We prove a Horrocks-type splitting criterion for arbitrary smooth projective toric varieties under an additional hypothesis similar to the case of products of projective spaces by Eisenbud--Erman--Schreyer.

Algebraic Geometry · Mathematics 2024-12-30 Mahrud Sayrafi

The Brill-Noether theory of curves plays a fundamental role in the theory of curves and their moduli and has been intensively studied since the 19th century. In contrast, Brill-Noether theory for higher dimensional varieties is less…

Algebraic Geometry · Mathematics 2024-09-27 Izzet Coskun , Jack Huizenga , Neelarnab Raha