{ "id": "2108.02639", "version": "v1", "published": "2021-08-05T14:25:28.000Z", "updated": "2021-08-05T14:25:28.000Z", "title": "Every $(13k-6)$-strong tournament with minimum out-degree at least $28k-13$ is $k$-linked", "authors": [ "Jørgen Bang-Jensen", "Kasper Skov Johansen" ], "categories": [ "math.CO" ], "abstract": "A digraph $D$ is $k$-linked if it satisfies that for every choice of disjoint sets $\\{x_1,\\ldots{},x_k\\}$ and $\\{y_1,\\ldots{},y_k\\}$ of vertices of $D$ there are vertex disjoint paths $P_1,\\ldots{},P_k$ such that $P_i$ is an $(x_i,y_i)$-path. Confirming a conjecture by K\\\"uhn et al, Pokrovskiy proved in 2015 that every $452k$-strong tournament is $k$-linked and asked for a better linear bound. Very recently Meng et al proved that every $(40k-31)$-strong tournament is $k$-linked. In this note we use an important lemma from their paper to give a short proof that every $(13k-6)$-strong tournament of minimum out-degree at least $28k-13$ is $k$-linked.", "revisions": [ { "version": "v1", "updated": "2021-08-05T14:25:28.000Z" } ], "analyses": { "subjects": [ "05C20", "05C40" ], "keywords": [ "strong tournament", "minimum out-degree", "vertex disjoint paths", "better linear bound", "disjoint sets" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }