{ "id": "1908.01375", "version": "v1", "published": "2019-08-04T17:14:43.000Z", "updated": "2019-08-04T17:14:43.000Z", "title": "Soluble Groups with few orbits under automorphisms", "authors": [ "Raimundo Bastos", "Alex Carrazedo Dantas", "Emerson de Melo" ], "comment": "Submitted to an international journal", "categories": [ "math.GR" ], "abstract": "Let $G$ be a group. The orbits of the natural action of $\\Aut(G)$ on $G$ are called ``automorphism orbits'' of $G$, and the number of automorphism orbits of $G$ is denoted by $\\omega(G)$. We prove that if $G$ is a soluble group with finite rank such that $\\omega(G)< \\infty$, then $G$ contains a torsion-free characteristic nilpotent subgroup $K$ such that $G = K \\rtimes H$, where $H$ is a finite group. Moreover, we classify the mixed order soluble groups of finite rank such that $\\omega(G)=3$.", "revisions": [ { "version": "v1", "updated": "2019-08-04T17:14:43.000Z" } ], "analyses": { "subjects": [ "20E22", "20E36" ], "keywords": [ "automorphism orbits", "finite rank", "torsion-free characteristic nilpotent subgroup", "mixed order soluble groups", "natural action" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }