{"title":"Claw-free cubic graphs are (1,1,2,2)-colorable","authors":"Boštjan Brešar , Kirsti Kuenzel , Douglas F. Rall","doi":"10.1016/j.disc.2025.114477","DOIUrl":null,"url":null,"abstract":"<div><div>A <span><math><mo>(</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span>-coloring of a graph is a partition of its vertex set into four sets two of which are independent and the other two are 2-packings. In this paper, we prove that every claw-free cubic graph admits a <span><math><mo>(</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span>-coloring. This implies that the conjecture from Brešar et al. (2017) <span><span>[5]</span></span> that the packing chromatic number of subdivisions of subcubic graphs is at most 5 is true in the case of claw-free cubic graphs.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"348 8","pages":"Article 114477"},"PeriodicalIF":0.7000,"publicationDate":"2025-03-14","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/S0012365X25000858","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
A -coloring of a graph is a partition of its vertex set into four sets two of which are independent and the other two are 2-packings. In this paper, we prove that every claw-free cubic graph admits a -coloring. This implies that the conjecture from Brešar et al. (2017) [5] that the packing chromatic number of subdivisions of subcubic graphs is at most 5 is true in the case of claw-free cubic graphs.
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.