{ "id": "2407.18258", "version": "v1", "published": "2024-07-11T15:38:21.000Z", "updated": "2024-07-11T15:38:21.000Z", "title": "On Galois covers of curves and arithmetic of Jacobians", "authors": [ "Alexandros Konstantinou", "Adam Morgan" ], "comment": "A significant part of this paper has been split out of the original version of arXiv:2211.06357. 27 pages, comments welcome", "categories": [ "math.NT" ], "abstract": "We study the arithmetic of curves and Jacobians endowed with the action of a finite group $G$. This includes a study of the basic properties, as $G$-modules, of their $\\ell$-adic representations, Selmer groups, rational points and Shafarevich-Tate groups. In particular, we show that $p^\\infty$-Selmer groups are self-dual $G$-modules, and give various `$G$-descent' results for Selmer groups and rational points. Along the way we revisit, and slightly refine, a construction going back to Kani and Rosen for associating isogenies to homomorphisms between permutation representations. With a view to future applications, it is convenient to work throughout with curves that are not assumed to be geometrically connected (or even connected); such curves arise naturally when taking Galois closures of covers of curves. For lack of a suitable reference, we carefully detail how to deduce the relevant properties of such curves and their Jacobians from the more standard geometrically connected case.", "revisions": [ { "version": "v1", "updated": "2024-07-11T15:38:21.000Z" } ], "analyses": { "subjects": [ "11G30", "11G10", "11G20", "14H25", "14H30", "14H40", "14K02" ], "keywords": [ "galois covers", "selmer groups", "arithmetic", "rational points", "shafarevich-tate groups" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable" } } }