{ "id": "2008.07639", "version": "v1", "published": "2020-08-17T21:45:31.000Z", "updated": "2020-08-17T21:45:31.000Z", "title": "Planar boundaries and parabolic subgroups", "authors": [ "G. Christopher Hruska", "Genevieve S. Walsh" ], "comment": "25 pages", "categories": [ "math.GR", "math.GT" ], "abstract": "We study the Bowditch boundaries of relatively hyperbolic group pairs, focusing on the case where there are no cut points. We show that, if there are parabolic inseparable cut pairs in $\\partial(G,\\mathcal{P})$, the group $G$ splits over a finite group. We use this to prove that when $G$ is one ended, and $(G, \\mathcal{P})$ is a relatively hyperbolic pair with connected planar boundary with no cut points, then every element of $\\mathcal{P}$ is virtually a surface group. This conclusion is consistent with the conjecture that such a group $G$ is virtually Kleinian. We give numerous examples to show the necessity of our assumptions.", "revisions": [ { "version": "v1", "updated": "2020-08-17T21:45:31.000Z" } ], "analyses": { "subjects": [ "20F67", "20E08" ], "keywords": [ "parabolic subgroups", "cut points", "relatively hyperbolic group pairs", "parabolic inseparable cut pairs", "connected planar boundary" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable" } } }