{ "id": "1612.01242", "version": "v1", "published": "2016-12-05T04:10:22.000Z", "updated": "2016-12-05T04:10:22.000Z", "title": "Properties of random nilpotent groups", "authors": [ "Albert Garreta", "Alexei Miasnikov", "Denis Ovchinnikov" ], "comment": "25 pages", "categories": [ "math.GR" ], "abstract": "We study random nilpotent groups of the form $G=N/\\langle\\langle R \\rangle \\rangle$, where $N$ is a non-abelian free nilpotent group with $m$ generators, and $R$ is a set of $r$ random relators of length $\\ell$. We prove that the following holds asymptotically almost surely as $\\ell\\to \\infty$: 1) If $r\\leq m-2$, then the ring of integers $\\mathbb{Z}$ is e-definable in $G/{it Is}(G_3)$, and systems of equations over $\\mathbb{Z}$ are reducible to systems of equations over $G$ (hence, they are undecidable). Moreover, $Z(G)\\leq {\\it Is}(G')$, $G/G_3$ is virtually free nilpotent of rank $m-r$, and $G/G_3$ cannot be decomposed as the direct product of two non-virtually abelian groups. 2) If $r=m-1$, then $G$ is virtually abelian. 3) If $r= m$, then $G$ is finite. 4) If $r\\geq m+1$, then $G$ is finite and abelian. In the last three cases, systems of equations are decidable in $G$.", "revisions": [ { "version": "v1", "updated": "2016-12-05T04:10:22.000Z" } ], "analyses": { "keywords": [ "properties", "study random nilpotent groups", "non-abelian free nilpotent group", "random relators", "virtually free nilpotent" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable" } } }