{ "id": "1908.06333", "version": "v1", "published": "2019-08-17T18:47:55.000Z", "updated": "2019-08-17T18:47:55.000Z", "title": "Asymptotic enumeration of linear hypergraphs with given number of vertices and edges", "authors": [ "Brendan D. McKay", "Fang Tian" ], "comment": "Submitted in January 2019", "categories": [ "math.CO" ], "abstract": "For $n\\geq 3$, let $r=r(n)\\geq 3$ be an integer. A hypergraph is $r$-uniform if each edge is a set of $r$ vertices, and is said to be linear if two edges intersect in at most one vertex. In this paper, the number of linear $r$-uniform hypergraphs on $n\\to\\infty$ vertices is determined asymptotically when the number of edges is $m(n)=o(r^{-3}n^{ \\frac32})$. As one application, we find the probability of linearity for the independent-edge model of random $r$-uniform hypergraph when the expected number of edges is $o(r^{-3}n^{ \\frac32})$. We also find the probability that a random $r$-uniform linear hypergraph with a given number of edges contains a given subhypergraph.", "revisions": [ { "version": "v1", "updated": "2019-08-17T18:47:55.000Z" } ], "analyses": { "subjects": [ "05C65", "05C80", "05A16" ], "keywords": [ "asymptotic enumeration", "uniform hypergraph", "uniform linear hypergraph", "independent-edge model", "probability" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }