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Related papers: Compactifications of Hurwitz spaces

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In this paper we show a general method to compactify certain open varieties by adding normal crossing divisors. This is done by proving that {\it blowing up along an arrangement of subvarieties} can be carried out. Important examples such…

Algebraic Geometry · Mathematics 2007-05-23 Yi Hu

We introduce a general abstract notion of fine compactified Jacobian for nodal curves of arbitrary genus. We focus on genus 1 and prove combinatorial classification results for fine compactified Jacobians in the case of a single nodal curve…

Algebraic Geometry · Mathematics 2022-03-01 Nicola Pagani , Orsola Tommasi

We derive a closed-form expression for all genus 1 Hurwitz numbers, and give a simple new graph-theoretic interpretation of Hurwitz numbers in genus 0 and 1. (Hurwitz numbers essentially count irreducible genus g covers of the sphere, with…

Combinatorics · Mathematics 2007-05-23 Ravi Vakil

Moduli spaces for Galois covers of p-adic Mumford curves by Mumford curves are constructed using Herrlich's Teichmuller spaces, Andre's orbifold fundamental groups, and Kato's graphs of groups encoding ramification data of charts for…

Algebraic Geometry · Mathematics 2007-05-23 Patrick Erik Bradley

While there is much work and many conjectures surrounding the intersection theory of the moduli space of curves, relatively little is known about the intersection theory of the Hurwitz space $\mathcal{H}_{k, g}$ parametrizing smooth degree…

Algebraic Geometry · Mathematics 2021-10-05 Samir Canning , Hannah Larson

We show that various loci of stable curves of sufficiently large genus admitting degree $d$ covers of positive genus curves define non-tautological algebraic cycles on $\overline{\mathcal{M}}_{g,N}$, assuming the non-vanishing of the $d$-th…

Algebraic Geometry · Mathematics 2021-10-06 Carl Lian

We consider the loci of curves of genus 2 and 3 admitting a $d$-to-1 map to a genus 1 curve. After compactifying these loci via admissible covers, we obtain formulas for their Chow classes, recovering results of Faber-Pagani and van Zelm…

Algebraic Geometry · Mathematics 2024-01-23 Carl Lian

Let $H$ be the Hilbert scheme of curves in complex projective $3$-space, with $d\geq 3$ and genus $g \leq (d-2)^2/4$. A complete, explicit description of the cone of curves and the ample cone of $H$ is given. From this, partial results on…

Algebraic Geometry · Mathematics 2019-05-17 Gerd Gotzmann

In this paper, we compute the number of covers of curves with given branch behavior in characteristic p for one class of examples with four branch points and degree p. Our techniques involve related computations in the case of three branch…

Algebraic Geometry · Mathematics 2009-06-10 Irene I. Bouw , Brian Osserman

We construct a relative compactification of Dolbeault moduli spaces of Higgs bundles for reductive algebraic groups on families of projective manifolds that is compatible with the Hitchin morphism.

Algebraic Geometry · Mathematics 2020-03-12 Mark Andrea A. de Cataldo

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

Here we focus on the compactification of the moduli space of curves of genus g together with an unramified double cover, constructed by Arnaud Beauville in order to compactify the Prym mapping. We present an alternative description of it,…

Algebraic Geometry · Mathematics 2007-05-23 Edoardo Ballico , Cinzia Casagrande , Claudio Fontanari

We show that the first cohomology group of the Hurwitz space of fully-marked admissible covers $H^1(\overline{\mathcal{H}}_{\underline{d},\underline{g}}(\underline{\mu}))$ vanishes for covers of degree $ d = 3$ and deduce the same result…

Algebraic Geometry · Mathematics 2025-12-02 Amy Q. Li

In 1969, Fulton introduced classical Hurwitz spaces parametrizing simple d-sheeted coverings of the projective line in the algebro-geometric setting. He established the irreducibility of these spaces under the assumption that the…

Algebraic Geometry · Mathematics 2026-05-26 Karl Christ , Xiang He , Ilya Tyomkin

We compute the rational Chow class of the locus of genus 2 curves admitting a d-to-1 map to a genus 1 curve, recovering a result of Faber-Pagani when d=2. The answer exhibits quasi-modularity properties similar to those in the Gromov-Witten…

Algebraic Geometry · Mathematics 2020-09-30 Carl Lian

In this expository note, we offer an overview of the relationship between Hodge-theoretic and geometric compactifications of moduli spaces of algebraic varieties.

Algebraic Geometry · Mathematics 2021-07-20 Patricio Gallardo , Matt Kerr

Branched covers are applied frequently in topology - most prominently in the construction of closed oriented PL d-manifolds. In particular, strong bounds for the number of sheets and the topology of the branching set are known for dimension…

Combinatorics · Mathematics 2008-01-23 Nikolaus Witte

In order to count the number of smooth cubic hypersurfaces tangent to a prescribed number of lines and passing through a given number of points, we construct a compactification of their moduli space. We term the latter a…

Algebraic Geometry · Mathematics 2022-01-17 Mara Belotti , Alessandro Danelon , Claudia Fevola , Andreas Kretschmer

In this paper we study the moduli spaces of nodal sextic curves. We realize each irreducible component of the GIT space of sextic curves with given number of nodes as an open subspace of type IV arithmetic quotients. We then focus on the…

Algebraic Geometry · Mathematics 2024-10-18 Chenglong Yu , Zhiwei Zheng

We are motivated by cone spherical metrics on compact Riemann surfaces of positive genus to solve a special case of the Hurwitz problem. Precisely speaking, letting $d,\,g$ and $\ell$ be three positive integers and $\Lambda$ be the…

Group Theory · Mathematics 2024-02-07 Jijian Song , Bin Xu , Yu Ye