{ "id": "1702.03060", "version": "v1", "published": "2017-02-10T03:53:20.000Z", "updated": "2017-02-10T03:53:20.000Z", "title": "A Variation of the Erdős-Sós Conjecture in Bipartite Graphs", "authors": [ "Long-Tu Yuan", "Xiao-Dong Zhang" ], "comment": "22 pages 2figures", "categories": [ "math.CO" ], "abstract": "The Erd\\H{o}s-S\\'{o}s Conjecture states that every graph with average degree more than $k-2$ contains all trees of order $k$ as subgraphs. In this paper, we consider a variation of the above conjecture: studying the maximum size of an $(n,m)$-bipartite graph which does not contain all $(k,l)$-bipartite trees for given integers $n\\ge m$ and $k\\ge l$. In particular, we determine that the maximum size of an $(n,m)$-bipartite graph which does not contain all $(n,m)$-bipartite trees as subgraphs (or all $(k,2)$-bipartite trees as subgraphs, respectively). Furthermore, all these extremal graphs are characterized.", "revisions": [ { "version": "v1", "updated": "2017-02-10T03:53:20.000Z" } ], "analyses": { "subjects": [ "05C35", "05C05" ], "keywords": [ "bipartite graph", "erdős-sós conjecture", "bipartite trees", "extremal graphs", "average degree" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable" } } }