{ "id": "1807.00085", "version": "v1", "published": "2018-06-29T23:37:34.000Z", "updated": "2018-06-29T23:37:34.000Z", "title": "Hurwitz numbers and integrable hierarchy of Volterra type", "authors": [ "Kanehisa Takasaki" ], "comment": "latex2e, amsmath,amssymb,amsthm, 12 pages, no figure", "categories": [ "math-ph", "hep-th", "math.MP", "math.QA", "nlin.SI" ], "abstract": "A generating function of the single Hurwitz numbers of the Riemann sphere $\\mathbb{CP}^1$ is a tau function of the lattice KP hierarchy. The associated Lax operator $L$ turns out to be expressed as $L = e^{\\mathfrak{L}}$, where $\\mathfrak{L}$ is a difference-differential operator of the form $\\mathfrak{L} = \\partial_s - ve^{-\\partial_s}$. $\\mathfrak{L}$ satisfies a set of Lax equations that form a continuum version of the Bogoyavlensky-Itoh (aka hungry Lotka-Volterra) hierarchies. Emergence of this underlying integrable structure is further explained in the language of generalized string equations for the Lax and Orlov-Schulman operators of the 2D Toda hierarchy. This leads to logarithmic string equations, which are confirmed with the help of a factorization problem of operators.", "revisions": [ { "version": "v1", "updated": "2018-06-29T23:37:34.000Z" } ], "analyses": { "subjects": [ "14N10", "37K10" ], "keywords": [ "volterra type", "integrable hierarchy", "2d toda hierarchy", "single hurwitz numbers", "aka hungry lotka-volterra" ], "note": { "typesetting": "LaTeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }