{ "id": "2401.05937", "version": "v1", "published": "2024-01-11T14:23:25.000Z", "updated": "2024-01-11T14:23:25.000Z", "title": "On the lattice of closed subgroups of a profinite group", "authors": [ "Francesco de Giovanni", "Iker de las Heras", "Marco Trombetti" ], "comment": "23 pages", "categories": [ "math.GR" ], "abstract": "The subgroup lattice of a group is a great source of information about the structure of the group itself. The aim of this paper is to use a similar tool for studying profinite groups. In more detail, we study the lattices of closed or open subgroups of a profinite group and its relation with the whole group. We show, for example, that procyclic groups are the only profinite groups with a distributive lattice of closed or open subgroups, and we give a sharp characterization of profinite groups whose lattice of closed (or open) subgroups satisfies the Dedekind modular law; we actually give a precise description of the behaviour of modular elements of the lattice of closed subgroups. We also deal with the problem of carrying some structural information from a profinite group to another one having an isomorphic lattice of closed (or open) subgroups. Some interesting consequences and related results concerning decomposability and the number of profinite groups with a given lattice of closed (or open) subgroups are also obtained.", "revisions": [ { "version": "v1", "updated": "2024-01-11T14:23:25.000Z" } ], "analyses": { "keywords": [ "closed subgroups", "open subgroups", "dedekind modular law", "studying profinite groups", "results concerning decomposability" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }