{ "id": "1303.4065", "version": "v1", "published": "2013-03-17T14:52:41.000Z", "updated": "2013-03-17T14:52:41.000Z", "title": "A construction of almost Steiner systems", "authors": [ "Asaf Ferber", "Rani Hod", "Michael Krivelevich", "Benny Sudakov" ], "categories": [ "math.CO" ], "abstract": "Let $n$, $k$, and $t$ be integers satisfying $n>k>t\\ge2$. A Steiner system with parameters $t$, $k$, and $n$ is a $k$-uniform hypergraph on $n$ vertices in which every set of $t$ distinct vertices is contained in exactly one edge. An outstanding problem in Design Theory is to determine whether a nontrivial Steiner system exists for $t\\geq6$. In this note we prove that for every $k>t\\ge2$ and sufficiently large $n$, there exists an almost Steiner system with parameters $t$, $k$, and $n$; that is, there exists a $k$-uniform hypergraph on $n$ vertices such that every set of $t$ distinct vertices is covered by either one or two edges.", "revisions": [ { "version": "v1", "updated": "2013-03-17T14:52:41.000Z" } ], "analyses": { "keywords": [ "construction", "uniform hypergraph", "distinct vertices", "nontrivial steiner system", "parameters" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1303.4065F" } } }