{"title":"极大外平面图的奇4着色","authors":"Masaki Kashima , Shun-ichi Maezawa , Kakeru Osako , Kenta Ozeki , Shoichi Tsuchiya","doi":"10.1016/j.disc.2025.114556","DOIUrl":null,"url":null,"abstract":"<div><div>An odd coloring of a graph <em>G</em> is a proper coloring with the following property: For every vertex <em>v</em> of <em>G</em>, there exists a color <em>i</em> such that there are an odd number of vertices of color <em>i</em> in the neighborhood of <em>v</em>. Caro, Petruševski, and Škrekovski proved that every outerplanar graph admits an odd 5-coloring. Since the cycle of length 5 does not admit an odd 4-coloring, this result is best possible. In this paper, we prove that every maximal outerplanar graph admits an odd 4-coloring. We also show that the list version holds.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"348 10","pages":"Article 114556"},"PeriodicalIF":0.7000,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"An odd 4-coloring of a maximal outerplanar graph\",\"authors\":\"Masaki Kashima , Shun-ichi Maezawa , Kakeru Osako , Kenta Ozeki , Shoichi Tsuchiya\",\"doi\":\"10.1016/j.disc.2025.114556\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>An odd coloring of a graph <em>G</em> is a proper coloring with the following property: For every vertex <em>v</em> of <em>G</em>, there exists a color <em>i</em> such that there are an odd number of vertices of color <em>i</em> in the neighborhood of <em>v</em>. Caro, Petruševski, and Škrekovski proved that every outerplanar graph admits an odd 5-coloring. Since the cycle of length 5 does not admit an odd 4-coloring, this result is best possible. In this paper, we prove that every maximal outerplanar graph admits an odd 4-coloring. We also show that the list version holds.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"348 10\",\"pages\":\"Article 114556\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-05-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0012365X25001645\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Discrete Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0012365X25001645","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
An odd coloring of a graph G is a proper coloring with the following property: For every vertex v of G, there exists a color i such that there are an odd number of vertices of color i in the neighborhood of v. Caro, Petruševski, and Škrekovski proved that every outerplanar graph admits an odd 5-coloring. Since the cycle of length 5 does not admit an odd 4-coloring, this result is best possible. In this paper, we prove that every maximal outerplanar graph admits an odd 4-coloring. We also show that the list version holds.
期刊介绍:
Discrete Mathematics provides a common forum for significant research in many areas of discrete mathematics and combinatorics. Among the fields covered by Discrete Mathematics are graph and hypergraph theory, enumeration, coding theory, block designs, the combinatorics of partially ordered sets, extremal set theory, matroid theory, algebraic combinatorics, discrete geometry, matrices, and discrete probability theory.
Items in the journal include research articles (Contributions or Notes, depending on length) and survey/expository articles (Perspectives). Efforts are made to process the submission of Notes (short articles) quickly. The Perspectives section features expository articles accessible to a broad audience that cast new light or present unifying points of view on well-known or insufficiently-known topics.