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Related papers: Hurwitz theory and the double ramification cycle

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We derive a formula for the virtual class of the moduli space of rubber maps to $[\mathbb{P}^1/G]$ pushed forward to the moduli space of stable maps to $BG$. As an application, we show that the Gromov-Witten theory of $[\mathbb{P}^1/G]$…

Algebraic Geometry · Mathematics 2020-08-04 Hsian-Hua Tseng , Fenglong You

We extend results by Mirzakhani in [Mir07] to moduli spaces of Hurwitz covers. In particular we obtain equations relating Weil-Petersson volumes of moduli spaces of Hurwitz covers, Hurwitz numbers and certain Hurwitz cycles on…

Symplectic Geometry · Mathematics 2017-11-21 Sven Prüfer

This article is an extended version of preprint math.AG/9902104. We find an explicit formula for the number of topologically different ramified coverings of a sphere by a genus g surface with only one complicated branching point in terms of…

Algebraic Geometry · Mathematics 2009-10-31 T. Ekedahl , S. Lando , M. Shapiro , A. Vainshtein

In this paper, using the formula for the integrals of the $\psi$-classes over the double ramification cycles found by S. Shadrin, L. Spitz, D. Zvonkine and the author, we derive a new explicit formula for the $n$-point function of the…

Algebraic Geometry · Mathematics 2017-05-22 Alexandr Buryak

We explain how logarithmic structures select principal components in an intersection of schemes. These manifest in Chow homology and can be understood using strict transforms under logarithmic blowups. Our motivation comes from…

Algebraic Geometry · Mathematics 2023-11-01 Sam Molcho , Dhruv Ranganathan

The Hurwitz space is a compactification of the space of rational functions of a given degree. The Lyashko-Looijenga map assigns to a rational function the set of its critical values. It is known that the number of ramified coverings of CP^1…

Algebraic Geometry · Mathematics 2007-05-23 Sergei Lando , Dimitri Zvonkine

We use algebraic methods to compute the simple Hurwitz numbers for arbitrary source and target Riemann surfaces. For an elliptic curve target, we reproduce the results previously obtained by string theorists. Motivated by the Gromov-Witten…

High Energy Physics - Theory · Physics 2015-06-25 Stefano Monni , Jun S. Song , Yun S. Song

In this paper, we study a certain type of Hurwitz numbers which count branched covers over the Riemann sphere admitting several branch points with fixed ramification types, one branch point with a fixed number of preimages, and one branch…

Combinatorics · Mathematics 2025-05-19 Zhiyuan Wang , Chenglang Yang

We discuss the open/closed version of the Gromov-Witten/Hurwitz correspondence. The duality equates the relative Gromov-Witten invariants and the count of covers of the target space with prescribed holonomies at boundaries. We clarify the…

High Energy Physics - Theory · Physics 2026-02-16 Jan Troost

We introduce new logarithmic Hurwitz spaces $\mathcal{LH}^{\mathbb{Z}_{(p)}}_A$ and $\mathcal{LH}^{\mathbb{F}_{p}}_{A,\Xi}$ over $\mathbb{Z}_{(p)}$ and $\mathbb{F}_p$ respectively that in the mixed characteristic case can be considered as a…

Algebraic Geometry · Mathematics 2026-02-19 Matthias Hippold

Simple Hurwitz numbers enumerate branched morphisms between Riemann surfaces with fixed ramification data. In recent years, several variants of this notion for genus $0$ base curves have appeared in the literature. Among them are so-called…

Algebraic Geometry · Mathematics 2022-11-02 Marvin Anas Hahn , Jan-Willem M. van Ittersum , Felix Leid

Monotone Hurwitz numbers were introduced by the authors as a combinatorially natural desymmetrization of the Hurwitz numbers studied in enumerative algebraic geometry. Over the course of several papers, we developed the structural theory of…

Combinatorics · Mathematics 2016-06-02 I. P. Goulden , Mathieu Guay-Paquet , Jonathan Novak

Let $R$ be a complete discrete valuation ring of equal characteristic $p>0$. Given a $\mathbb{Z}/p$-Galois cover of a formal disc over $R$, one can derive from it a semi-stable model for which the specializations of branch points are…

Algebraic Geometry · Mathematics 2021-01-05 Huy Dang

New Frobenius structures on Hurwitz spaces are found. A Hurwitz space is considered as a real manifold; therefore the number of coordinates is twice as large as the number of coordinates on Hurwitzs Frobenius manifolds of Dubrovin. Simple…

Mathematical Physics · Physics 2009-11-10 Vasilisa Shramchenko

This is the first of two papers on the uniform asymptotics for real double Hurwitz numbers with triple ramification. Real double Hurwitz numbers with triple ramification count the number of real ramified coverings of the complex projective…

Algebraic Geometry · Mathematics 2026-02-05 Yanqiao Ding , Kui Li , Huan Liu , Dongfeng Yan

We construct several modular compactifications of the Hurwitz space $H^d_{g/h}$ of genus $g$ curves expressed as $d$-sheeted, simply branched covers of genus $h$ curves. These compactifications are obtained by allowing the branch points of…

Algebraic Geometry · Mathematics 2012-06-21 Anand Deopurkar

Double Hurwitz numbers count covers of the projective line by genus g curves with assigned ramification profiles over 0 and infinity, and simple ramification over a fixed branch divisor. Goulden, Jackson and Vakil have shown double Hurwitz…

Algebraic Geometry · Mathematics 2010-03-10 Renzo Cavalieri , Paul Johnson , Hannah Markwig

We calculate the cycle class of the Hurwitz divisor $D_2$ on the moduli space of stable curves of genus $g=2k$ given by the degree $k+1$ covers of the projective line with simple ramification points, two of which lie in the same fibre. We…

Algebraic Geometry · Mathematics 2010-08-10 Gerard van der Geer , Alexis Kouvidakis

This paper has the purpose of presenting in an organic way a new approach to integrable (1+1)-dimensional field systems and their systematic quantization emerging from intersection theory of the moduli space of stable algebraic curves and,…

Mathematical Physics · Physics 2017-08-01 Paolo Rossi

Hurwitz numbers count genus $g$, degree $d$ covers of the complex projective line with fixed branched locus and fixed ramification data. An equivalent description is given by factorisations in the symmetric group. Simple double Hurwitz…

Combinatorics · Mathematics 2019-04-05 Marvin Anas Hahn