{ "id": "2308.14778", "version": "v1", "published": "2023-08-28T13:34:50.000Z", "updated": "2023-08-28T13:34:50.000Z", "title": "A precise condition for independent transversals in bipartite covers", "authors": [ "Stijn Cambie", "Penny Haxell", "Ross J. Kang", "Ronen Wdowinski" ], "comment": "10 pages, 2 figures", "categories": [ "math.CO", "cs.DM" ], "abstract": "Given a bipartite graph $H=(V=V_A\\cup V_B,E)$ in which any vertex in $V_A$ (resp. $V_B$) has degree at most $D_A$ (resp. $D_B$), suppose there is a partition of $V$ that is a refinement of the bipartition $V_A\\cup V_B$ such that the parts in $V_A$ (resp. $V_B$) have size at least $k_A$ (resp. $k_B$). We prove that the condition $D_A/k_A+D_B/k_B\\le 1$ is sufficient for the existence of an independent set of vertices of $H$ that is simultaneously transversal to the partition, and show moreover that this condition is sharp. This result is a bipartite refinement of two well-known results on independent transversals, one due to the second author the other due to Szab\\'o and Tardos.", "revisions": [ { "version": "v1", "updated": "2023-08-28T13:34:50.000Z" } ], "analyses": { "subjects": [ "05C69", "05D15", "05C15", "05C35" ], "keywords": [ "independent transversals", "bipartite covers", "precise condition", "independent set", "bipartite graph" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }