{ "id": "0903.2520", "version": "v1", "published": "2009-03-14T00:56:44.000Z", "updated": "2009-03-14T00:56:44.000Z", "title": "On Point Sets in Vector Spaces over Finite Fields That Determine Only Acute Angle Triangles", "authors": [ "Igor E. Shparlinski" ], "categories": [ "math.NT", "math.CO" ], "abstract": "For three points $\\vec{u}$,$\\vec{v}$ and $\\vec{w}$ in the $n$-dimensional space $\\F_q^n$ over the finite field $\\F_q$ of $q$ elements we give a natural interpretation of an acute angle triangle defined by this points. We obtain an upper bound on the size of a set $\\cZ$ such that all triples of distinct points $\\vec{u}, \\vec{v}, \\vec{w} \\in \\cZ$ define acute angle triangles. A similar question in the real space $\\cR^n$ dates back to P. Erd{\\H o}s and has been studied by several authors.", "revisions": [ { "version": "v1", "updated": "2009-03-14T00:56:44.000Z" } ], "analyses": { "subjects": [ "05B25", "11T23", "52C10" ], "keywords": [ "finite field", "vector spaces", "point sets", "define acute angle triangles", "upper bound" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0903.2520S" } } }