{ "id": "2202.02586", "version": "v1", "published": "2022-02-05T15:58:11.000Z", "updated": "2022-02-05T15:58:11.000Z", "title": "A note on odd-coloring 1-planar graphs", "authors": [ "Michael Lafferty", "Zi-Xia Song" ], "categories": [ "math.CO" ], "abstract": "A proper coloring of a graph is odd if every non-isolated vertex has some color that appears an odd number of times on its neighborhood. This notion was recently introduced by Petru\\v{s}evski and \\v{S}krekovski, who proved that every planar graph admits an odd $9$-coloring; they also conjectured that every planar graph admits an odd $5$-coloring. Shortly after, this conjecture was confirmed for planar graphs of girth at least seven by Cranston; outerplanar graphs by Caro, Petru\\v{s}evski and \\v{S}krekovski. Building on the work of Caro, Petru\\v{s}evski and \\v{S}krekovski, Petr and Portier then further proved that every planar graph admits an odd $8$-coloring. In this note we prove that every 1-planar graph admits an odd $47$-coloring, where a graph is 1-planar if it can be drawn in the plane so that each edge is crossed by at most one other edge.", "revisions": [ { "version": "v1", "updated": "2022-02-05T15:58:11.000Z" } ], "analyses": { "keywords": [ "planar graph admits", "odd number", "odd-coloring", "outerplanar graphs", "non-isolated vertex" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }