{ "id": "2203.11099", "version": "v1", "published": "2022-03-21T16:26:54.000Z", "updated": "2022-03-21T16:26:54.000Z", "title": "A quantitative Neumann lemma for finitely generated groups", "authors": [ "Elia Gorokhovsky", "Nicolás Matte Bon", "Omer Tamuz" ], "comment": "8 pages", "categories": [ "math.GR" ], "abstract": "We study the coset covering function $\\mathfrak{C}(r)$ of a finitely generated group: the number of cosets of infinite index subgroups needed to cover the ball of radius $r$. We show that $\\mathfrak{C}(r)$ is linear for virtually nilpotent groups, exponential for property (T) groups, and is of order at least $\\sqrt{r}$ for all groups.", "revisions": [ { "version": "v1", "updated": "2022-03-21T16:26:54.000Z" } ], "analyses": { "keywords": [ "finitely generated group", "quantitative neumann lemma", "infinite index subgroups", "coset covering function", "virtually nilpotent groups" ], "note": { "typesetting": "TeX", "pages": 8, "language": "en", "license": "arXiv", "status": "editable" } } }