{ "id": "1908.04902", "version": "v1", "published": "2019-08-14T00:57:30.000Z", "updated": "2019-08-14T00:57:30.000Z", "title": "3-choosable planar graphs with some precolored vertices and no $5^{-}$-cycles normally adjacent to $8^{-}$-cycles", "authors": [ "Fangyao Lu", "Qianqian Wang", "Tao Wang" ], "comment": "9 pages, 2 figures", "categories": [ "math.CO", "cs.DM" ], "abstract": "DP-coloring was introduced by Dvo\\v{r}\\'{a}k and Postle [J. Combin. Theory Ser. B 129 (2018) 38--54] as a generalization of list coloring. They used a \"weak\" version of DP-coloring to solve a longstanding conjecture by Borodin, stating that every planar graph without cycles of length $4$ to $8$ is $3$-choosable. Liu and Li improved the result by showing that every planar graph without adjacent cycles of length at most $8$ is $3$-choosable. In this paper, it is showed that every planar graph without $5^{-}$-cycles normally adjacent to $8^{-}$-cycles is $3$-choosable. Actually, all these three papers give more stronger results by stating them in the form of \"weakly\" DP-$3$-coloring and color extension.", "revisions": [ { "version": "v1", "updated": "2019-08-14T00:57:30.000Z" } ], "analyses": { "subjects": [ "05C15" ], "keywords": [ "planar graph", "cycles normally adjacent", "precolored vertices", "theory ser", "adjacent cycles" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }