{ "id": "2305.01193", "version": "v1", "published": "2023-05-02T04:01:15.000Z", "updated": "2023-05-02T04:01:15.000Z", "title": "Wickets in 3-uniform Hypergraphs", "authors": [ "Jozsef Solymosi" ], "categories": [ "math.CO" ], "abstract": "In these notes, we consider a Tur\\'an-type problem in hypergraphs. What is the maximum number of edges if we forbid a subgraph? Let $H_n^{(3)}$ be a 3-uniform linear hypergraph, i.e. any two edges have at most one vertex common. A special hypergraph, called {\\em wicket}, is formed by three rows and two columns of a $3 \\times 3$ point matrix. We describe two linear hypergraphs -- both containing a wicket -- that if we forbid either of them in $H_n^{(3)}$, then the hypergraph is sparse, and the number of its edges is $o(n^2)$. This proves a conjecture of Gy\\'arf\\'as and S\\'ark\\\"ozy.", "revisions": [ { "version": "v1", "updated": "2023-05-02T04:01:15.000Z" } ], "analyses": { "keywords": [ "linear hypergraph", "turan-type problem", "maximum number", "vertex common", "special hypergraph" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }