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Related papers: Around spin Hurwitz numbers

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Double Hurwitz numbers enumerating weighted $n$-sheeted branched coverings of the Riemann sphere or, equivalently, weighted paths in the Cayley graph of $S_n$ generated by transpositions are determined by an associated weight generating…

Mathematical Physics · Physics 2018-06-26 Mathieu Guay-Paquet , J. Harnad

We continue the investigation of the connection between the genus expansion of matrix models and the $\hbar$ expansion of integrable hierarchies started in arXiv:2008.06416. In this paper, we focus on the $B$KP hierarchy, which corresponds…

High Energy Physics - Theory · Physics 2023-05-26 Yaroslav Drachov , Aleksandr Zhabin

This is an overview of recent results on the use of 2D Toda $\tau$-functions as generating functions for multiparametric families of weighted Hurwitz numbers. The Bose-Fermi equivalence composed with the characteristic map provides an…

Mathematical Physics · Physics 2018-06-26 J. Harnad

Hurwitz numbers enumerate ramified coverings of the Riemann sphere with fixed ramification data. Certain kinds of ramification data are of particular interest, such as double Hurwitz numbers, which count covers with fixed arbitrary…

Combinatorics · Mathematics 2018-10-09 Marvin Anas Hahn

Hurwitz numbers count ramified genus $g$, degree $d$ coverings of the projective line with with fixed branch locus and fixed ramification data. Double Hurwitz numbers count such covers, where we fix two special profiles over $0$ and…

Combinatorics · Mathematics 2018-07-11 Marvin Anas Hahn

We demonstrate that statistics of certain classes of set partitions is described by generating functions related to the Burgers, Ibragimov--Shabat and Korteweg--de Vries integrable hierarchies.

Exactly Solvable and Integrable Systems · Physics 2015-07-07 V. E. Adler

We study cut-and-join operators for spin Hurwitz partition functions. We provide explicit expressions for these operators in terms of derivatives in $p$-variables without straightforward matrix realization, which is yet to be found. With…

High Energy Physics - Theory · Physics 2022-06-07 A. Mironov , A. Morozov , A. Zhabin

The KP hierarchy is a completely integrable system of quadratic, partial differential equations that generalizes the KdV hierarchy. A linear combination of Schur functions is a solution to the KP hierarchy if and only if its coefficients…

Combinatorics · Mathematics 2008-03-28 I. P. Goulden , D. M. Jackson

The KP and 2D Toda tau-functions of hypergeometric type that serve as generating functions for weighted single and double Hurwitz numbers are related to the topological recursion programme. A graphical representation of such weighted…

Mathematical Physics · Physics 2021-03-04 A. Alexandrov , G. Chapuy , B. Eynard , J. Harnad

We introduce a new generalization of Stirling numbers of the second kind and analyze their properties, including generating functions, integral representations, and recurrence relations. These numbers are used to approximate Riemann zeta…

Number Theory · Mathematics 2025-10-09 Kamel Mezlini , Tahar Moumni , Najib Ouled Azaiez

Multiparametric families of hypergeometric $\tau$-functions of KP or Toda type serve as generating functions for weighted Hurwitz numbers, providing weighted enumerations of branched covers of the Riemann sphere. A graphical interpretation…

Mathematical Physics · Physics 2019-07-02 A. Alexandrov , G. Chapuy , B. Eynard , J. Harnad

In this paper we describe explicit generating functions for a large class of Hurwitz-Hodge integrals. These are integrals of tautological classes on moduli spaces of admissible covers, a (stackily) smooth compactification of the Hurwitz…

Algebraic Geometry · Mathematics 2007-05-23 Renzo Cavalieri

The construction of hypergeometric 2D Toda $\tau$-functions as generating functions for quantum Hurwitz numbers is extended here to multispecies families. Both the enumerative geometrical significance of these multispecies quantum Hurwitz…

Mathematical Physics · Physics 2016-11-01 J. Harnad

Double Hurwitz numbers enumerate branched covers of $\mathbb{CP}^1$ with prescribed ramification over two points and simple ramification elsewhere. In contrast to the single case, their underlying geometry is not well understood. In…

Algebraic Geometry · Mathematics 2023-07-07 Gaëtan Borot , Norman Do , Maksim Karev , Danilo Lewański , Ellena Moskovsky

A fermionic representation is given for all the quantities entering in the generating function approach to weighted Hurwitz numbers and topological recursion. This includes: KP and 2D Toda $\tau$-functions of hypergeometric type, which…

Mathematical Physics · Physics 2023-08-08 A. Alexandrov , G. Chapuy , B. Eynard , J. Harnad

We are extending results from \cite{B-Hurwitz} by building a parallel theory of simple Hurwitz numbers for the reflection groups $G(m,1,n)$. We also study analogs of the cut-and-join operators. An algebraic description as well as a…

Combinatorics · Mathematics 2024-03-05 Raphaël Fesler , Denis Gorodkov , Maksim Karev

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

We study multi-matrix models which may be viewed as integrals of products of tau functions which depend on the eigenvalues of products of random matrices. In the present paper we consider tau functions of the hierarchy the two-component KP…

Mathematical Physics · Physics 2017-10-24 A. Yu. Orlov

The construction of hypergeometric $2D$ Toda $\tau$-functions as generating functions for weighted Hurwitz numbers is extended to multispecies families. Both the enumerative geometrical significance of multispecies weighted Hurwitz numbers,…

Mathematical Physics · Physics 2018-06-26 J. Harnad

In this paper, we prove that the generalized Br\'ezin-Gross-Witten tau-function is a hypergeometric solution of the BKP hierarchy with simple weight generating function. We claim that it describes a spin version of the strictly monotone…

Mathematical Physics · Physics 2022-12-13 Alexander Alexandrov