{ "id": "1510.07156", "version": "v1", "published": "2015-10-24T15:51:21.000Z", "updated": "2015-10-24T15:51:21.000Z", "title": "Existence and non-existence of bounded packing in CAT(0) spaces and Gromov hyperbolic spaces", "authors": [ "Pranab Sardar" ], "categories": [ "math.GR", "math.GT" ], "abstract": "The main result of this paper is that given a group $G$ acting geometrically by isometries on a CAT(0) space $X$ and a cyclic subgroup $H$ of $G$ generated by a rank-1 isometry of $X$, $H$ has bounded packing in $G$. We give two proofs of this result. The first one is by a characterization of rank-$1$ isometries by Hamenstadt. The second proof follows directly from some results of Dahmani-Guirardel-Osin and Sisto. Then using Mihailova's construction, we show the existence of a finitely generated subgroup of the direct product of two free groups $\\mathbb F_2\\times \\mathbb F_2$ without the bounded packing property answering a question of Hruska-Wise. We also prove the existence of finitely presented subgroups of CAT(0) groups without bounded packing using Wise's {\\em modified Rip's construction} and the {\\bf 1-2-3} theorem of Baumslag, Bridson, Miller and Short.", "revisions": [ { "version": "v1", "updated": "2015-10-24T15:51:21.000Z" } ], "analyses": { "keywords": [ "gromov hyperbolic spaces", "bounded packing", "non-existence", "cyclic subgroup", "main result" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv151007156S" } } }