{"title":"Infinitely many minimally non-Ramsey size-linear graphs","authors":"Yuval Wigderson","doi":"10.1016/j.ejc.2025.104175","DOIUrl":null,"url":null,"abstract":"<div><div>A graph <span><math><mi>G</mi></math></span> is said to be Ramsey size-linear if <span><math><mrow><mi>r</mi><mrow><mo>(</mo><mi>G</mi><mo>,</mo><mi>H</mi><mo>)</mo></mrow><mo>=</mo><msub><mrow><mi>O</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>e</mi><mrow><mo>(</mo><mi>H</mi><mo>)</mo></mrow><mo>)</mo></mrow></mrow></math></span> for every graph <span><math><mi>H</mi></math></span> with no isolated vertices. Erdős, Faudree, Rousseau, and Schelp observed that <span><math><msub><mrow><mi>K</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> is not Ramsey size-linear, but each of its proper subgraphs is, and they asked whether there exist infinitely many such graphs. In this short note, we answer this question in the affirmative.</div></div>","PeriodicalId":50490,"journal":{"name":"European Journal of Combinatorics","volume":"128 ","pages":"Article 104175"},"PeriodicalIF":0.9000,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Combinatorics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0195669825000605","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
A graph is said to be Ramsey size-linear if for every graph with no isolated vertices. Erdős, Faudree, Rousseau, and Schelp observed that is not Ramsey size-linear, but each of its proper subgraphs is, and they asked whether there exist infinitely many such graphs. In this short note, we answer this question in the affirmative.
期刊介绍:
The European Journal of Combinatorics is a high standard, international, bimonthly journal of pure mathematics, specializing in theories arising from combinatorial problems. The journal is primarily open to papers dealing with mathematical structures within combinatorics and/or establishing direct links between combinatorics and other branches of mathematics and the theories of computing. The journal includes full-length research papers on important topics.