{ "id": "2406.02792", "version": "v1", "published": "2024-06-04T21:32:35.000Z", "updated": "2024-06-04T21:32:35.000Z", "title": "Weak Degeneracy of Planar Graphs", "authors": [ "Anton Bernshteyn", "Eugene Lee", "Evelyne Smith-Roberge" ], "comment": "12 pages, 3 figures", "categories": [ "math.CO" ], "abstract": "The weak degeneracy of a graph $G$ is a numerical parameter that was recently introduced by the first two authors with the aim of understanding the power of greedy algorithms for graph coloring. Every $d$-degenerate graph is weakly $d$-degenerate, but the converse is not true in general (for example, all connected $d$-regular graphs except cycles and cliques are weakly $(d-1)$-degenerate). If $G$ is weakly $d$-degenerate, then the list-chromatic number of $G$ is at most $d+1$, and the same upper bound holds for various other parameters such as the DP-chromatic number and the paint number. Here we rectify a mistake in a paper of the first two authors and give a correct proof that planar graphs are weakly $4$-degenerate, strengthening the famous result of Thomassen that planar graphs are $5$-list-colorable.", "revisions": [ { "version": "v1", "updated": "2024-06-04T21:32:35.000Z" } ], "analyses": { "keywords": [ "planar graphs", "weak degeneracy", "upper bound holds", "correct proof", "regular graphs" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }