{ "id": "2009.10144", "version": "v1", "published": "2020-09-21T19:24:57.000Z", "updated": "2020-09-21T19:24:57.000Z", "title": "Sharp upper bounds on the length of the shortest closed geodesic on complete punctured spheres of finite area", "authors": [ "Antonia Jabbour", "Stéphane Sabourau" ], "categories": [ "math.DG" ], "abstract": "We establish sharp universal upper bounds on the length of the shortest closed geodesic on a punctured sphere with three or four ends endowed with a complete Riemannian metric of finite area. These sharp curvature-free upper bounds are expressed in terms of the area of the punctured sphere. In both cases, we describe the extremal metrics, which are modeled on the Calabi-Croke sphere or the tetrahedral sphere. We also extend these optimal inequalities for reversible and non-necessarily reversible Finsler metrics. In this setting, we obtain optimal bounds for spheres with a larger number of punctures. Finally, we present a roughly asymptotically optimal upper bound on the length of the shortest closed geodesic for spheres/surfaces with a large number of punctures in terms of the area.", "revisions": [ { "version": "v1", "updated": "2020-09-21T19:24:57.000Z" } ], "analyses": { "keywords": [ "shortest closed geodesic", "sharp upper bounds", "complete punctured spheres", "finite area", "sharp universal upper bounds" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }