{ "id": "1702.02631", "version": "v1", "published": "2017-02-08T21:59:16.000Z", "updated": "2017-02-08T21:59:16.000Z", "title": "Self-linked sets in finite groups", "authors": [ "Taras Banakh", "Volodymyr Gavrylkiv" ], "comment": "6 pages", "categories": [ "math.CO", "math.GR" ], "abstract": "A subset $A$ of a group $G$ is called self-linked if $A\\cap gA\\ne\\emptyset$ for every $g\\in G$. The smallest cardinality $|A|$ of a self-linked subset $A\\subset G$ is called the self-linked number $sl(G)$ of $G$. In the paper we find lower and upper bounds for the self-linked number $sl(G)$ of a finite group $G$ and prove that $$\\frac{1+\\sqrt{4|G|+4|G_2|-7}}2\\le sl(G)\\le \\frac{\\sqrt[4]{|G|\\ln(|G|-1)}+\\sqrt{\\ln 4}}{\\sqrt[4]{|G|\\ln(|G|-1)}-\\sqrt{\\ln 4}}\\cdot \\sqrt{|G|\\ln(|G|-1)}$$where $G_2=\\{g\\in G:g^{-1}=g\\}$ is the set of elements of order at most two in $G$. Also we calculate the self-linked numbers of all Abelian groups of cardinality $\\le95$.", "revisions": [ { "version": "v1", "updated": "2017-02-08T21:59:16.000Z" } ], "analyses": { "subjects": [ "05E15" ], "keywords": [ "finite group", "self-linked sets", "self-linked number", "abelian groups", "smallest cardinality" ], "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable" } } }