{ "id": "2004.05433", "version": "v1", "published": "2020-04-11T16:02:21.000Z", "updated": "2020-04-11T16:02:21.000Z", "title": "Clique immersions in graphs with certain forbidden subgraphs", "authors": [ "Daniel A. Quiroz" ], "comment": "13 pages, 3 figures", "categories": [ "math.CO" ], "abstract": "The Lescure-Meyniel conjecture is the analogue of Hadwiger's conjecture for the immersion order. It states that every graph $G$ contains the complete graph $K_{\\chi(G)}$ as an immersion, and like its minor-order counterpart it is open even for graphs with independence number 2. We show that every graph $G$ with independence number $\\alpha(G)\\ge 2$ and no hole of length between $4$ and $2\\alpha(G)$ satisfies this conjecture. In particular, every $C_4$-free graph $G$ with $\\alpha(G)= 2$ satisfies the Lescure-Meyniel conjecture. We give another generalisation of this corollary, as follows. Let $G$ and $H$ be graphs with independence number at most 2, such that $|V(H)|\\le 4$. If $G$ is $H$-free, then $G$ satisfies the Lescure-Meyniel conjecture.", "revisions": [ { "version": "v1", "updated": "2020-04-11T16:02:21.000Z" } ], "analyses": { "subjects": [ "05C15", "05C69" ], "keywords": [ "forbidden subgraphs", "clique immersions", "independence number", "lescure-meyniel conjecture", "immersion order" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable" } } }