{ "id": "2505.07873", "version": "v1", "published": "2025-05-09T22:12:51.000Z", "updated": "2025-05-09T22:12:51.000Z", "title": "Solution to two open problems in geometric group theory", "authors": [ "Jordan A. Sahattchieve" ], "comment": "Ph.D. dissertation, University of Michigan in Ann Arbor, 2012, 88 pages", "journal": "Groups Complex. Cryptol Vol. 7 No. 1 (2015); Serdica Math. J. 48 (2022)", "categories": [ "math.GR" ], "abstract": "We introduce a method for analyzing the convex hull of a set in non-positively curved piecewise Euclidean polygonal complexes and we apply this method to prove that with the usual action of Fm x Zn on the metric product of a tree with Rn , every quasiconvex subgroup of Fm x Zn is convex. This answers the question whether a quasiconvex subgroup of a CAT(0) group is a CAT(0) group in the affirmative for the groups F m x Zn. We also prove bounded packing in a special class of polycyclic groups, and we introduce the notion of coset growth and provide a bound for the coset growth of uniform lattices in Sol.", "revisions": [ { "version": "v1", "updated": "2025-05-09T22:12:51.000Z" } ], "analyses": { "subjects": [ "20F65", "20F67", "20F16", "20F19" ], "keywords": [ "geometric group theory", "open problems", "coset growth", "quasiconvex subgroup", "curved piecewise euclidean polygonal complexes" ], "tags": [ "dissertation", "journal article" ], "note": { "typesetting": "TeX", "pages": 88, "language": "en", "license": "arXiv", "status": "editable" } } }