{ "id": "2310.06354", "version": "v1", "published": "2023-10-10T06:43:57.000Z", "updated": "2023-10-10T06:43:57.000Z", "title": "Transversals in a collections of trees", "authors": [ "Ethan Y. H. Li", "Luyi Li", "Ping Li" ], "comment": "16pages,2figures", "categories": [ "math.CO" ], "abstract": "Let $\\mathcal{S}$ be a fixed family of graphs on vertex set $V$ and $\\mathcal{G}$ be a collection of elements in $\\mathcal{S}$. We investigated the transversal problem of finding the maximum value of $|\\mathcal{G}|$ when $\\mathcal{G}$ contains no rainbow elements in $\\mathcal{S}$. Specifically, we determine the exact values when $\\mathcal{S}$ is a family of stars or a family of trees of the same order $n$ with $n$ dividing $|V|$. Further, all the extremal cases for $\\mathcal{G}$ are characterized.", "revisions": [ { "version": "v1", "updated": "2023-10-10T06:43:57.000Z" } ], "analyses": { "subjects": [ "05C15", "05C05", "05D15" ], "keywords": [ "collection", "exact values", "vertex set", "rainbow elements", "maximum value" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }