{ "id": "1307.8135", "version": "v1", "published": "2013-07-30T20:14:33.000Z", "updated": "2013-07-30T20:14:33.000Z", "title": "Irrational numbers associated to sequences without geometric progressions", "authors": [ "Melvyn B. Nathanson", "Kevin O'Bryant" ], "comment": "7 pages", "categories": [ "math.NT" ], "abstract": "Let s and k be integers with s \\geq 2 and k \\geq 2. Let g_k^{(s)}(n) denote the cardinality of the largest subset of the set {1,2,..., n} that contains no geometric progression of length k whose common ratio is a power of s. Let r_k(\\ell) denote the cardinality of the largest subset of the set {0,1,2,\\ldots, \\ell -1\\} that contains no arithmetric progression of length k. The limit \\[ \\lim_{n\\rightarrow \\infty} \\frac{g_k^{(s)}(n)}{n} = (s-1) \\sum_{m=1}^{\\infty} \\left(\\frac{1}{s} \\right)^{\\min \\left(r_k^{-1}(m)\\right)} \\] exists and converges to an irrational number.", "revisions": [ { "version": "v1", "updated": "2013-07-30T20:14:33.000Z" } ], "analyses": { "subjects": [ "11B05", "11B25", "11B75", "11B83", "05D10", "11J99" ], "keywords": [ "geometric progression", "irrational numbers", "largest subset", "cardinality", "common ratio" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1307.8135N" } } }