{ "id": "1510.05998", "version": "v1", "published": "2015-10-20T18:14:08.000Z", "updated": "2015-10-20T18:14:08.000Z", "title": "Extractors in Paley graphs: a random model", "authors": [ "Rudi Mrazović" ], "comment": "11 pages", "categories": [ "math.CO", "math.NT" ], "abstract": "A well-known conjecture in analytic number theory states that for every pair of sets $X,Y\\subset\\mathbb{Z}/p\\mathbb{Z}$, each of size at least $\\log ^C p$ (for some constant $C$) we have that for $(\\frac12+o(1))|X||Y|$ of the pairs $(x,y)\\in X\\times Y$, $x+y$ is a quadratic residue modulo $p$. We address the probabilistic analogue of this question, that is for every fixed $\\delta>0$, given a finite group $G$ and $A\\subset G$ a random subset of density $\\frac12$, we prove that with high probability for all subsets $|X|,|Y|\\geq \\log ^{2+\\delta} |G|$ for $(\\frac12+o(1))|X||Y|$ of the pairs $(x,y)\\in X\\times Y$ we have $xy\\in A$.", "revisions": [ { "version": "v1", "updated": "2015-10-20T18:14:08.000Z" } ], "analyses": { "keywords": [ "random model", "paley graphs", "extractors", "analytic number theory states", "quadratic residue modulo" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }