{ "id": "1907.01720", "version": "v1", "published": "2019-07-03T03:06:17.000Z", "updated": "2019-07-03T03:06:17.000Z", "title": "Clique immersions and independence number", "authors": [ "Sebastián Bustamante", "Daniel A. Quiroz", "Maya Stein", "José Zamora" ], "comment": "12 pages, 1 figure", "categories": [ "math.CO" ], "abstract": "The analogue of Hadwiger's conjecture for the immersion order states that every graph $G$ contains $K_{\\chi (G)}$ as an immersion. If true, it would imply that every graph with $n$ vertices and independence number $\\alpha$ contains $K_{\\lceil \\frac n\\alpha\\rceil}$ as an immersion. The best currently known bound for this conjecture is due to Gauthier, Le and Wollan, who recently proved that every graph $G$ contains an immersion of a clique on $\\bigl\\lceil \\frac{\\chi (G)-4}{3.54}\\bigr\\rceil$ vertices. Their result implies that every $n$-vertex graph with independence number $\\alpha$ contains an immersion of a clique on $\\bigl\\lceil \\frac{n}{3.54\\alpha}-1.13\\bigr\\rceil$ vertices. We improve on this result for all $\\alpha\\ge 3$, by showing that every $n$-vertex graph with independence number $\\alpha\\ge 3$ contains an immersion of a clique on $\\bigl\\lfloor \\frac {4n}{9 (\\alpha -1)} \\bigr\\rfloor - \\lfloor \\frac{\\alpha}2 \\rfloor$ vertices.", "revisions": [ { "version": "v1", "updated": "2019-07-03T03:06:17.000Z" } ], "analyses": { "keywords": [ "independence number", "clique immersions", "vertex graph", "immersion order states", "result implies" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }