{ "id": "1803.10179", "version": "v3", "published": "2018-03-27T16:53:45.000Z", "updated": "2018-08-23T10:03:24.000Z", "title": "Integrals of groups", "authors": [ "João Araújo", "Peter J. Cameron", "Carlo Casolo", "Francesco Matucci" ], "comment": "31 pages, no figures; new co-author and new title; the previous posting has been split in half, with the second part to be expanded and resubmitted separately", "categories": [ "math.GR" ], "abstract": "An $integral$ of a group $G$ is a group $H$ whose derived group (commutator subgroup) is isomorphic to $G$. This paper discusses integrals of groups, and in particular questions about which groups have integrals and how big or small those integrals can be. Our main results are: (1) If a finite group has an integral, then it has a finite integral. (2) A precise characterization of the set of natural numbers $n$ for which every group of order $n$ is integrable: these are the cubefree numbers $n$ which do not have prime divisors $p$ and $q$ with $q\\mid p-1$. (3) An abelian group of order $n$ has an integral of order at most $n^{1+o(1)}$, but may fail to have an integral of order bounded by $cn$ for constant $c$. (4) A finite group can be integrated $n$ times (in the class of finite groups) if and only if it is the central product of an abelian group and a perfect group. There are many other results on such topics as centreless groups, groups with composition length $2$, and infinite groups. We also include a number of open problems.", "revisions": [ { "version": "v3", "updated": "2018-08-23T10:03:24.000Z" } ], "analyses": { "subjects": [ "20D99", "20D25" ], "keywords": [ "abelian group", "paper discusses integrals", "cubefree numbers", "main results", "commutator subgroup" ], "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable" } } }