{ "id": "1708.02855", "version": "v1", "published": "2017-08-09T14:31:29.000Z", "updated": "2017-08-09T14:31:29.000Z", "title": "Local cut points and splittings of relatively hyperbolic groups", "authors": [ "Matthew Haulmark" ], "comment": "35 pages", "categories": [ "math.GR", "math.GT" ], "abstract": "In this paper we show that the existence of a non-parabolic local cut point in the Bowditch boundary $\\partial(G,\\mathbb{P})$ of a relatively hyperbolic group $(G,\\mathbb{P})$ implies that $G$ splits over a $2$-ended subgroup. This theorem generalizes a theorem of Bowditch from the setting of hyperbolic groups to relatively hyperbolic groups. As a consequence we are able to generalize a theorem of Kapovich and Kleiner by classifying the homeomorphism type of $1$-dimensional Bowditch boundaries of relatively hyperbolic groups which satisfy certain properties, such as no splittings over $2$-ended subgroups and no peripheral splittings. In order to prove the boundary classification result we require a notion of ends of a group which is more general than the standard notion. We show that if a finitely generated discrete group acts properly and cocompactly on two generalized Peano continua $X$ and $Y$, then $Ends(X)$ is homeomorphic to $Ends(Y)$. Thus we propose an alternate definition of $Ends(G)$ which increases the class of spaces on which $G$ can act.", "revisions": [ { "version": "v1", "updated": "2017-08-09T14:31:29.000Z" } ], "analyses": { "subjects": [ "20F65", "20F67" ], "keywords": [ "relatively hyperbolic group", "generated discrete group acts", "splittings", "non-parabolic local cut point", "bowditch boundary" ], "note": { "typesetting": "TeX", "pages": 35, "language": "en", "license": "arXiv", "status": "editable" } } }