{ "id": "2110.01281", "version": "v6", "published": "2021-10-04T09:45:03.000Z", "updated": "2022-08-23T07:57:02.000Z", "title": "Forbidden subgraphs and 2-factors in 3/2-tough graphs", "authors": [ "Masahiro Sanka" ], "comment": "16 pages, 3 figures", "categories": [ "math.CO" ], "abstract": "A graph $G$ is $H$-free if it has no induced subgraph isomorphic to $H$, where $H$ is a graph. In this paper, we show that every $\\frac{3}{2}$-tough $(P_4 \\cup P_{10})$-free graph has a 2-factor. The toughness condition of this result is sharp. Moreover, for any $\\varepsilon>0$ there exists a $(2-\\varepsilon)$-tough $2P_5$-free graph without a 2-factor. This implies that the graph $P_4 \\cup P_{10}$ is best possible for a forbidden subgraph in a sense.", "revisions": [ { "version": "v6", "updated": "2022-08-23T07:57:02.000Z" } ], "analyses": { "subjects": [ "05C38", "05C42", "05C45" ], "keywords": [ "forbidden subgraph", "free graph", "toughness condition", "induced subgraph isomorphic" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }