{"title":"On equitably 2-colourable odd cycle decompositions","authors":"Andrea Burgess, Francesca Merola","doi":"10.1002/jcd.21937","DOIUrl":null,"url":null,"abstract":"<p>An <span></span><math>\n \n <mrow>\n <mi>ℓ</mi>\n </mrow></math>-cycle decomposition of <span></span><math>\n \n <mrow>\n <msub>\n <mi>K</mi>\n \n <mi>v</mi>\n </msub>\n </mrow></math> is said to be <i>equitably 2-colourable</i> if there is a 2-vertex-colouring of <span></span><math>\n \n <mrow>\n <msub>\n <mi>K</mi>\n \n <mi>v</mi>\n </msub>\n </mrow></math> such that each colour is represented (approximately) an equal number of times on each cycle: more precisely, we ask that in each cycle <span></span><math>\n \n <mrow>\n <mi>C</mi>\n </mrow></math> of the decomposition, each colour appears on <span></span><math>\n \n <mrow>\n <mrow>\n <mo>⌊</mo>\n \n <mrow>\n <mi>ℓ</mi>\n \n <mo>∕</mo>\n \n <mn>2</mn>\n </mrow>\n \n <mo>⌋</mo>\n </mrow>\n </mrow></math> or <span></span><math>\n \n <mrow>\n <mrow>\n <mo>⌈</mo>\n \n <mrow>\n <mi>ℓ</mi>\n \n <mo>∕</mo>\n \n <mn>2</mn>\n </mrow>\n \n <mo>⌉</mo>\n </mrow>\n </mrow></math> of the vertices of <span></span><math>\n \n <mrow>\n <mi>C</mi>\n </mrow></math>. In this paper we study the existence of equitably 2-colourable <span></span><math>\n \n <mrow>\n <mi>ℓ</mi>\n </mrow></math>-cycle decompositions of <span></span><math>\n \n <mrow>\n <msub>\n <mi>K</mi>\n \n <mi>v</mi>\n </msub>\n </mrow></math>, where <span></span><math>\n \n <mrow>\n <mi>ℓ</mi>\n </mrow></math> is odd, and prove the existence of such a decomposition for <span></span><math>\n \n <mrow>\n <mi>v</mi>\n \n <mo>≡</mo>\n \n <mn>1</mn>\n \n <mo>,</mo>\n \n <mi>ℓ</mi>\n </mrow></math> (mod <span></span><math>\n \n <mrow>\n <mn>2</mn>\n \n <mi>ℓ</mi>\n </mrow></math>).</p>","PeriodicalId":15389,"journal":{"name":"Journal of Combinatorial Designs","volume":"32 8","pages":"419-437"},"PeriodicalIF":0.5000,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jcd.21937","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Combinatorial Designs","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jcd.21937","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
An -cycle decomposition of is said to be equitably 2-colourable if there is a 2-vertex-colouring of such that each colour is represented (approximately) an equal number of times on each cycle: more precisely, we ask that in each cycle of the decomposition, each colour appears on or of the vertices of . In this paper we study the existence of equitably 2-colourable -cycle decompositions of , where is odd, and prove the existence of such a decomposition for (mod ).
期刊介绍:
The Journal of Combinatorial Designs is an international journal devoted to the timely publication of the most influential papers in the area of combinatorial design theory. All topics in design theory, and in which design theory has important applications, are covered, including:
block designs, t-designs, pairwise balanced designs and group divisible designs
Latin squares, quasigroups, and related algebras
computational methods in design theory
construction methods
applications in computer science, experimental design theory, and coding theory
graph decompositions, factorizations, and design-theoretic techniques in graph theory and extremal combinatorics
finite geometry and its relation with design theory.
algebraic aspects of design theory.
Researchers and scientists can depend on the Journal of Combinatorial Designs for the most recent developments in this rapidly growing field, and to provide a forum for both theoretical research and applications. All papers appearing in the Journal of Combinatorial Designs are carefully peer refereed.