{ "id": "1202.0667", "version": "v2", "published": "2012-02-03T11:26:52.000Z", "updated": "2012-02-06T10:04:43.000Z", "title": "Additive colorings of planar graphs", "authors": [ "Tomasz Bartnicki", "Bartłomiej Bosek", "Sebastian Czerwiński", "Jarosław Grytczuk", "Grzegorz Matecki", "Wiktor Żelazny" ], "categories": [ "math.CO" ], "abstract": "An \\emph{additive coloring} of a graph $G$ is an assignment of positive integers $\\{1,2,...,k\\}$ to the vertices of $G$ such that for every two adjacent vertices the sums of numbers assigned to their neighbors are different. The minimum number $k$ for which there exists an additive coloring of $G$ is denoted by $\\eta (G)$. We prove that $\\eta (G)\\leqslant 468$ for every planar graph $G$. This improves a previous bound $\\eta (G)\\leqslant 5544$ due to Norin. The proof uses Combinatorial Nullstellensatz and coloring number of planar hypergrahs. We also demonstrate that $\\eta (G)\\leqslant 36$ for 3-colorable planar graphs, and $\\eta (G)\\leqslant 4$ for every planar graph of girth at least 13. In a group theoretic version of the problem we show that for each $r\\geqslant 2$ there is an $r$-chromatic graph $G_{r}$ with no additive coloring by elements of any Abelian group of order $r$.", "revisions": [ { "version": "v2", "updated": "2012-02-06T10:04:43.000Z" } ], "analyses": { "keywords": [ "planar graph", "additive coloring", "group theoretic version", "adjacent vertices", "combinatorial nullstellensatz" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1202.0667B" } } }