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Related papers: Tropicalising hypergeometric $\tau$-functions

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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 introduce a scheme-theoretic enrichment of the principal objects of tropical geometry. Using a category of semiring schemes, we construct tropical hypersurfaces as schemes over idempotent semirings such as $\mathbb{T} = (\mathbb{R}\cup…

Algebraic Geometry · Mathematics 2017-02-22 Jeffrey Giansiracusa , Noah Giansiracusa

Tropical geometry is a piecewise linear "shadow" of algebraic geometry. It allows for the computation of several cohomological invariants of an algebraic variety. In particular, its application to enumerative algebraic geometry led to…

Algebraic Geometry · Mathematics 2012-06-12 Florian Block

Hurwitz numbers count branched covers of the Riemann sphere with specified ramification data, or equivalently, transitive permutation factorizations in the symmetric group with specified cycle types. Monotone Hurwitz numbers count a…

Combinatorics · Mathematics 2019-08-15 I. P. Goulden , Mathieu Guay-Paquet , Jonathan Novak

This work concerns the semiclassical asymptotics of quantum weighted double Hurwitz numbers. We compute the leading term of the partition function for three versions of the quantum weighted Hurwitz numbers, as well as lower order…

Mathematical Physics · Physics 2016-11-01 J. Harnad , Janosch Ortmann

We find a relation between mixed volumes of several polytopes and the convex hull of their union, deducing it from the following fact: the mixed volume of a collection of polytopes only depends on the product of their support functions…

Algebraic Geometry · Mathematics 2018-01-31 Alexander Esterov

We present a review of the spin Hurwitz numbers, which count the ramified coverings with spin structures. They are related to peculiar $Q$ Schur functions, which are actually related to characters of the Sergeev group. This allows one to…

Mathematical Physics · Physics 2021-10-15 A. D. Mironov , A. Yu Morozov , S. M. Natanzon , A. Yu Orlov

We generalize the determinant representation of the KP $\tau$ functions to the case of the 2D Toda $\tau$ functions. The generating functions for the weighted Hurwitz numbers are a parametric family of 2D Toda $\tau$ functions; for which we…

Mathematical Physics · Physics 2023-01-18 Xiang-Mao Ding , Xiang Li

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

We introduce a two-parameter refinement of the Jucys-Murphy theory, that we call the CJT-refinement, unifying Schur, zonal, and, conjecturally, Jack actions of the ring of symmetric functions on the Fock space. Applications of this…

Combinatorics · Mathematics 2025-08-11 Raphaël Fesler , Marvin Anas Hahn , Maksim Karev , Hannah Markwig

We give a natural definition of open Hurwitz numbers, where the weight of each ramified covering includes an integer parameter $N$ taken to the power that is equal to the number of boundary components of a Riemann surface with boundary…

Mathematical Physics · Physics 2025-10-10 Alexandr Buryak , Ran J. Tessler , Mikhail Troshkin

We investigate the combinatorics of real double Hurwitz numbers with real positive branch points using the symmetric group. Our main focus is twofold. First, we prove correspondence theorems relating these numbers to counts of tropical real…

Algebraic Geometry · Mathematics 2019-10-14 Mathieu Guay-Paquet , Hannah Markwig , Johannes Rau

A multiparametric family of 2D Toda $\tau$-functions of hypergeometric type is shown to provide generating functions for composite, signed Hurwitz numbers that enumerate certain classes of branched coverings of the Riemann sphere and paths…

Mathematical Physics · Physics 2017-02-06 J. Harnad , A. Yu. Orlov

Let $X = X_\Sigma$ be a toric surface and $(\check{X}, W)$ be its Landau-Ginzburg (LG) mirror where $W$ is the Hori-Vafa potential. We apply asymptotic analysis to study the extended deformation theory of the LG model $(\check{X}, W)$, and…

Algebraic Geometry · Mathematics 2020-09-10 Kwokwai Chan , Ziming Nikolas Ma

We study the geometry of tropical extensions of hyperfields, including the ordinary, signed and complex tropical hyperfields. We introduce the framework of 'enriched valuations' as hyperfield homomorphisms to tropical extensions, and show…

Algebraic Geometry · Mathematics 2024-11-27 James Maxwell , Ben Smith

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

In this paper we study relations between intersection numbers on moduli spaces of curves and Hurwitz numbers. First, we prove two formulas expressing Hurwitz numbers of (generalized) polynomials via intersections on moduli spaces of curves.…

Algebraic Geometry · Mathematics 2010-10-04 Sergei Shadrin

We use tropical and nonarchimedean geometry to study the moduli space of genus $0$ stable maps to $\mathbb{P}^1$ relative to two points. This space is exhibited as a tropical compactification in a toric variety. Moreover, the fan of this…

Algebraic Geometry · Mathematics 2017-06-06 Renzo Cavalieri , Hannah Markwig , Dhruv Ranganathan

Motivated by results for the HCIZ integral in Part I of this paper, we study the structure of monotone Hurwitz numbers, which are a desymmetrized version of classical Hurwitz numbers. We prove a number of results for monotone Hurwitz…

Combinatorics · Mathematics 2011-07-07 Ian P. Goulden , Mathieu Guay-Paquet , Jonathan Novak

In this paper we use the connections between tropical algebraic geometry and rigid analytic geometry in order to prove two main results. We use tropical methods to prove a theorem about the Newton polygon for convergent power series in…

Algebraic Geometry · Mathematics 2010-07-19 Joseph Rabinoff