{ "id": "1502.03704", "version": "v1", "published": "2015-02-12T15:39:42.000Z", "updated": "2015-02-12T15:39:42.000Z", "title": "Improved bounds for arithmetic progressions in product sets", "authors": [ "Dmitry Zhelezov" ], "comment": "To appear in Int. J. Number Theory", "categories": [ "math.NT" ], "abstract": "Let $B$ be a set of natural numbers of size $n$. We prove that the length of the longest arithmetic progression contained in the product set $B.B = \\{bb'| \\, b, b' \\in B\\}$ cannot be greater than $O(n \\log n)$ which matches the lower bound provided in an earlier paper up to a multiplicative constant. For sets of complex numbers we improve the bound to $O_\\epsilon(n^{1 + \\epsilon})$ for arbitrary $\\epsilon > 0$ assuming the GRH.", "revisions": [ { "version": "v1", "updated": "2015-02-12T15:39:42.000Z" } ], "analyses": { "subjects": [ "11B25" ], "keywords": [ "product set", "lower bound", "longest arithmetic progression", "natural numbers", "earlier paper" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }