{ "id": "2112.10864", "version": "v2", "published": "2021-12-20T21:19:05.000Z", "updated": "2022-03-16T19:14:30.000Z", "title": "Moduli spaces of Riemann surfaces as Hurwitz spaces", "authors": [ "Andrea Bianchi" ], "comment": "52 pages, 5 figures; the introduction has been changed", "categories": [ "math.AT" ], "abstract": "We consider the moduli space $\\mathfrak{M}_{g,n}$ of Riemann surfaces of genus $g\\ge0$ with $n\\ge1$ ordered and directed marked points. For $d\\ge 2g+n-1$, we show that $\\mathfrak{M}_{g,n}$ is homotopy equivalent to a component of the generalised Hurwitz space $\\mathrm{Hur}^{\\Delta}(\\mathfrak{S}_d^{\\mathrm{geo}})$, associated with the partially multiplicative quandle $\\mathfrak{S}_d^{\\mathrm{geo}}$. As an application, we give a new proof of the Mumford conjecture on the stable rational cohomology of moduli spaces of Riemann surfaces. We also provide a combinatorial model for the infinite loop space $\\Omega^{\\infty-2}\\mathrm{MTSO}(2)$ of Hurwitz flavour.", "revisions": [ { "version": "v2", "updated": "2022-03-16T19:14:30.000Z" } ], "analyses": { "subjects": [ "55P35", "55P62", "55R80", "57T25" ], "keywords": [ "moduli space", "riemann surfaces", "infinite loop space", "generalised hurwitz space", "homotopy equivalent" ], "note": { "typesetting": "TeX", "pages": 52, "language": "en", "license": "arXiv", "status": "editable" } } }