{ "id": "1812.01350", "version": "v1", "published": "2018-12-04T11:51:13.000Z", "updated": "2018-12-04T11:51:13.000Z", "title": "Expansive Automorphisms on Locally Compact Groups", "authors": [ "Riddh Shah" ], "comment": "18 pages", "categories": [ "math.DS", "math.GR" ], "abstract": "We show that any connected locally compact group which admits an expansive automorphism is nilpotent. We also show that for any locally compact group $G$, $\\alpha\\in {\\rm Aut}(G)$ is expansive if and only if for any $\\alpha$-invariant closed subgroup $H$ which is either compact or normal, the restriction of $\\alpha$ to $H$ is expansive and the quotient map on $G/H$ corresponding to $\\alpha$ is expansive. We get a structure theorem for locally compact groups admitting expansive automorphisms. We prove that an automorphism on a non-discrete locally compact group can not be both distal and expansive.", "revisions": [ { "version": "v1", "updated": "2018-12-04T11:51:13.000Z" } ], "analyses": { "subjects": [ "22D05", "22D45", "37B05", "37A25", "22E25" ], "keywords": [ "compact groups admitting expansive automorphisms", "non-discrete locally compact group", "invariant closed subgroup", "quotient map", "connected locally compact group" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }