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Analogue of classical Hurwitz numbers is defined in the work for regular coverings of surfaces with marked points by seamed surfaces. Class of surfaces includes surfaces of any genus and orientability, with or without boundaries; coverings…

Geometric Topology · Mathematics 2007-09-25 A. V. Alexeevski , S. M. Natanzon

Given a spectral curve with exponential singularities (which we call a "transalgebraic spectral curve"), we extend the definition of topological recursion to include contributions from the exponential singularities in a way that is…

Mathematical Physics · Physics 2025-09-03 Vincent Bouchard , Reinier Kramer , Quinten Weller

In this paper, we presents a method for factoring morphisms between arithmetic surfaces based on the regularity of arithmetic surfaces. Using this factorization, we derive a Riemann-Hurwitz formula satisfied by the ramification divisor and…

Algebraic Geometry · Mathematics 2025-12-04 Ziyang Zhu

We study the interplay between the classical theory of linear series on curves, and the recent theory of linear series on graphs. We prove that every d-gonal (weighted) graph of Hurwitz type is the dual graph of a d-gonal curve. Conversely…

Algebraic Geometry · Mathematics 2013-07-23 Lucia Caporaso

Moduli spaces of algebraic curves and closely related to them Hurwitz spaces, that is, spaces of meromorphic functions on the curves, arise naturally in numerous problems of algebraic geometry and mathematical physics, especially in…

Algebraic Geometry · Mathematics 2015-06-26 M. E. Kazaryan , S. K. Lando

Motivated by the problem of Hurwitz equivalence of $\Delta ^2$ factorization in the braid group, we address the problem of Hurwitz equivalence in the symmetric group, obtained by projecting the $\Delta ^2$ factorizations into $S_n$. We get…

Algebraic Geometry · Mathematics 2007-05-23 M. Teicher , T. Ben-Itzhak

In general, Hurwitz numbers count branched covers of the Riemann sphere with prescribed ramification data, or equivalently, factorisations in the symmetric group with prescribed cycle structure data. In this paper, we initiate the study of…

Geometric Topology · Mathematics 2015-11-10 Norman Do , Maksim Karev

This paper is the third part of the series "Spherical higher order Fourier analysis over finite fields", aiming to develop the higher order Fourier analysis method along spheres over finite fields, and to solve the geometric Ramsey…

Number Theory · Mathematics 2024-07-29 Wenbo Sun

We classify Nichols algebras of irreducible Yetter-Drinfeld modules over groups such that the underlying rack is braided and the homogeneous component of degree three of the Nichols algebra satisfies a given inequality. This assumption…

Quantum Algebra · Mathematics 2012-03-07 I. Heckenberger , A. Lochmann , L. Vendramin

We prove the Lefschetz hyperplane section theorem using a simpler machinery by making the observation that we can compose the Lefschetz Pencil with a Real Morse function to get a map from the variety to $\mathbb{R}$ which is "close" to…

Algebraic Geometry · Mathematics 2021-07-07 Nima Rose Manjila , A. J. Parameswaran

We consider algorithms that, from an arbitrarily sampling of $N$ spheres (possibly overlapping), find a close packed configuration without overlapping. These problems can be formulated as minimization problems with non-convex constraints.…

Numerical Analysis · Mathematics 2017-01-04 Pierre Degond , Marina A. Ferreira , Sébastien Motsch

We present a new proof of Witten's conjecture. The proof is based on the analysis of the relationship between intersection indices on moduli spaces of complex curves and Hurwitz numbers enumerating ramified coverings of the 2-sphere.

Algebraic Geometry · Mathematics 2015-06-26 M. E. Kazarian , S. K. Lando

We propose a new, conjectural recursion solution for Hurwitz numbers at all genera. This conjecture is based on recent progress in solving type B topological string theory on the mirrors of toric Calabi-Yau manifolds, which we briefly…

Algebraic Geometry · Mathematics 2008-12-04 Vincent Bouchard , Marcos Marino

In this paper we prove certain Hurwitz equivalence properties in $B_n$. Our main result is that every two Artin's factorizations of $\Delta_n ^2$ of the form $H_{i_1} ... H_{i_{n(n-1)}}, \quad F_{j_1} ... F_{j_{n(n-1)}}$ (with $i_k, j_k \in…

Algebraic Geometry · Mathematics 2007-05-23 M. Teicher , T. Ben-Itzhak

In contrast to all other known Ramanujan-type congruences, we discover that Ramanujan-type congruences for Hurwitz class numbers can be supported on non-holomorphic generating series. We establish a divisibility result for such…

Number Theory · Mathematics 2022-05-25 Olivia Beckwith , Martin Raum , Olav K. Richter

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

Tyomkin's correspondence theorem states the equality of counts of rational curves of fixed homology class in a toric surface satisfying point and cross-ratio conditions with their tropical counterparts. Such correspondence theorems allow us…

Algebraic Geometry · Mathematics 2025-08-21 Parisa Ebrahimian

We study a generalization of the Harish-Chandra - Itzykson - Zuber integral to tensors and its expansion over trace-invariants of the two external tensors. This gives rise to natural generalizations of monotone double Hurwitz numbers, which…

Combinatorics · Mathematics 2023-10-25 Benoît Collins , Razvan Gurau , Luca Lionni

The Hurwitz space is a compactification of the space of rational functions of a given degree. We study the intersection of various strata of this space with its boundary. A study of the cohomology ring of the Hurwitz space then allows us to…

Algebraic Geometry · Mathematics 2007-05-23 Dimitri Zvonkine

The classical Sturm-Hurwitz-Kellogg theorem asserts that a function, orthogonal to an n-dimensional Chebyshev system on a circle, has at least n+1 sign changes. We prove the converse: given an n-dimensional Chebyshev system on a circle and…

Differential Geometry · Mathematics 2007-11-01 S. Tabachnikov