{ "id": "1809.07445", "version": "v1", "published": "2018-09-20T01:49:54.000Z", "updated": "2018-09-20T01:49:54.000Z", "title": "DP-3-coloring of planar graphs without $4,9$-cycles and two cycles from $\\{5,6,7,8\\}$", "authors": [ "Runrun Liu", "Sarah Loeb", "Martin Rolek", "Yuxue Yin", "Gexin Yu" ], "categories": [ "math.CO" ], "abstract": "A generalization of list-coloring, now known as DP-coloring, was recently introduced by Dvo\\v{r}\\'{a}k and Postle. Essentially, DP-coloring assigns an arbitrary matching between lists of colors at adjacent vertices, as opposed to only matching identical colors as is done for list-coloring. Several results on list-coloring of planar graphs have since been extended to the setting of DP-coloring. We note that list-coloring results do not always extend to DP-coloring results. Our main result in this paper is to prove that every planar graph without cycles of length $\\{4, a, b, 9\\}$ for $a, b \\in \\{6, 7, 8\\}$ is DP-$3$-colorable, extending three existing results on $3$-choosability of planar graphs.", "revisions": [ { "version": "v1", "updated": "2018-09-20T01:49:54.000Z" } ], "analyses": { "keywords": [ "planar graph", "adjacent vertices", "main result", "generalization", "identical colors" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }