{ "id": "2308.05442", "version": "v1", "published": "2023-08-10T08:58:12.000Z", "updated": "2023-08-10T08:58:12.000Z", "title": "Optimal chromatic bound for ($P_3\\cup P_2$, house)-free graphs", "authors": [ "Rui Li", "Di Wu", "Jinfeng Li" ], "comment": "arXiv admin note: text overlap with arXiv:2307.11946", "categories": [ "math.CO" ], "abstract": "Let $G$ and $H$ be two vertex disjoint graphs. The {\\em union} $G\\cup H$ is the graph with $V(G\\cup H)=V(G)\\cup V(H)$ and $E(G\\cup H)=E(G)\\cup E(H)$. We use $P_k$ to denote a {\\em path} on $k$ vertices, use {\\em house} to denote the complement of $P_5$. In this paper, we show that $\\chi(G)\\le2\\omega(G)$ if $G$ is ($P_3\\cup P_2$, house)-free. Moreover, this bound is optimal when $\\omega(G)\\ge2$.", "revisions": [ { "version": "v1", "updated": "2023-08-10T08:58:12.000Z" } ], "analyses": { "keywords": [ "optimal chromatic bound", "vertex disjoint graphs", "complement" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }