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Related papers: Orbifold Hurwitz numbers and Eynard-Orantin invari…

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Let G be the group A_4 or Z_2xZ_2. We compute the integral of \lambda_g on the Hurwitz locus H_G\subset M_g of curves admitting a degree 4 cover of P^1 having monodromy group G. We compute the generating functions for these integrals and…

Algebraic Geometry · Mathematics 2007-09-03 Jim Bryan , Amin Gholampour

Hurwitz numbers enumerate branched morphisms between Riemannn surfaces with fixed numerical data. They represent important objects in enumerative geometry that are accessible by combinatorial techniques. In the past decade, many variants of…

Combinatorics · Mathematics 2023-10-10 Sean Gearoid Fitzgerald , Marvin Anas Hahn , Síofra Kelly

We prove an all genera version of the Crepant Resolution Conjecture of Ruan and Bryan-Graber for type A surface singularities. We are based on a method that explicitly computes Hurwitz-Hodge integrals described in an earlier paper and some…

Algebraic Geometry · Mathematics 2008-11-14 Jian Zhou

We give an approach for relative and degenerate Gromov--Witten invariants, inspired by that of Jun Li but replacing predeformable maps by transversal maps to a twisted target. The main advantage is a significant simplification in the…

Algebraic Geometry · Mathematics 2014-08-06 Dan Abramovich , Barbara Fantechi

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

We show that the Poincare polynomial associated with the orbifold cell decomposition of the moduli space of smooth algebraic curves with distinct marked points satisfies a topological recursion formula of the Eynard-Orantin type. The…

Algebraic Geometry · Mathematics 2014-11-05 Motohico Mulase , Michael Penkava

We prove that single $G$-weighted $\mathfrak{b}$-Hurwitz numbers with internal faces are computed by refined topological recursion on a rational spectral curve, for certain rational weights $G$. Consequently, the $\mathfrak{b}$-Hurwitz…

Combinatorics · Mathematics 2026-03-17 Nitin Kumar Chidambaram , Maciej Dołęga , Kento Osuga

Hurwitz spaces which parametrize branched covers of the line play a prominent role in inverse Galois theory. This paper surveys fifty years of works in this direction with emphasis on recent advances. Based on the Riemann-Hurwitz theory of…

Number Theory · Mathematics 2026-04-14 Pierre Dèbes

We consider a generalized Riemann-Hurwitz formula as it may be applied to rational maps between projective varieties having an indeterminacy set and fold-like singularities. The case of a holomorphic branched covering map is recalled. Then…

Algebraic Topology · Mathematics 2016-02-10 James F. Glazebrook , Alberto Verjovsky

After defining generalizations of the notions of covariant derivatives and geodesics from Riemannian geometry for reductive Cartan geometries in general, various results for reductive Cartan geometries analogous to important elementary…

Differential Geometry · Mathematics 2023-07-06 Jacob W. Erickson

Recently a new family of enumerative invariants called leaky Hurwitz numbers was introduced by Cavalieri-Markwig-Ranganathan in the context of logarithmic intersection theory. They admit an interpretation via tropical covers where the…

Algebraic Geometry · Mathematics 2026-03-09 Marvin Anas Hahn , Reinier Kramer

Spin Hurwitz numbers count ramified covers of a spin surface, weighted by the size of their automorphism group (like ordinary Hurwitz numbers), but signed $\pm 1$ according to the parity of the covering surface. These numbers were first…

Quantum Algebra · Mathematics 2016-09-21 Sam Gunningham

For orbifolds admitting a crepant resolution and satisfying a hard Lefschetz condition, we formulate a conjectural equivalence between the Gromov-Witten theories of the orbifold and the resolution. We prove the conjecture for the…

Algebraic Geometry · Mathematics 2007-05-23 Jim Bryan , Tom Graber

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 define a new Hurwitz problem which is essentially a small core of the simple Hurwitz problem. The corresponding Hurwitz numbers have simpler formulae, satisfy effective recursion relations and determine the simple Hurwitz numbers. We…

Geometric Topology · Mathematics 2013-12-31 Norman Do , Paul Norbury

We give a new proof of the cut-and-join equation for the monotone Hurwitz numbers, derived first by Goulden, Guay-Paquet, and Novak. Our proof in particular uses a combinatorial technique developed by Han. The main interest in this…

Algebraic Geometry · Mathematics 2019-05-16 Petr Dunin-Barkowski , Reinier Kramer , Alexandr Popolitov , Sergey Shadrin

We introduce a one-parameter deformation of the 2-Toda tau-function of (weighted) Hurwitz numbers, obtained by deforming Schur functions into Jack symmetric functions. We show that its coefficients are polynomials in the deformation…

Combinatorics · Mathematics 2022-09-13 Guillaume Chapuy , Maciej Dołęga

The orbifold braid groups of two dimensional orbifolds were defined in [1] (arXiv:math/9907194) to understand certain Artin groups as subgroups of some suitable orbifold braid groups. We studied orbifold braid groups in some more detail in…

Group Theory · Mathematics 2023-09-08 S. K. Roushon

We study a $b$-deformation of monotone Hurwitz numbers, obtained by deforming Schur functions into Jack symmetric functions. We give an evolution equation for this model and derive from it Virasoro constraints, thereby proving a conjecture…

Combinatorics · Mathematics 2023-12-18 Valentin Bonzom , Guillaume Chapuy , Maciej Dołęga

We present several recent developments on ELSV-type formulae and topological recursion concerning Chiodo classes and several kind of Hurwitz numbers. The main results appeared in D. Lewanski, A. Popolitov, S. Shadrin, D. Zvonkine, "Chiodo…

Algebraic Geometry · Mathematics 2017-03-21 Danilo Lewanski