Gabriel Ferreira Barros, Bruno Pasqualotto Cavalar, Y. Kohayakawa, Guilherme Oliveira Mota, Tássio Naia
{"title":"具有较低定向拉姆齐阈值的有向图","authors":"Gabriel Ferreira Barros, Bruno Pasqualotto Cavalar, Y. Kohayakawa, Guilherme Oliveira Mota, Tássio Naia","doi":"10.1051/ro/2024090","DOIUrl":null,"url":null,"abstract":"We investigate the threshold [[EQUATION]] for the Ramsey-type property [[EQUATION]], where [[EQUATION]] is the binomial random graph and [[EQUATION]] indicates that every orientation of the graph [[EQUATION]] contains the oriented graph [[EQUATION]] as a subdigraph. Similarly to the classical Ramsey setting, the upper bound [[EQUATION]] is known to hold for some constant [[EQUATION]], where [[EQUATION]] denotes the maximum 2-density of the underlying graph [[EQUATION]] of [[EQUATION]]. While this upper bound is indeed the threshold for some [[EQUATION]], this is not always the case. We obtain examples arising from rooted products of orientations of sparse graphs (such as forests, cycles and, more generally, subcubic [[EQUATION]]-free graphs) and arbitrarily rooted transitive triangles.","PeriodicalId":506995,"journal":{"name":"RAIRO - Operations Research","volume":"13 6","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Directed graphs with lower orientation Ramsey thresholds\",\"authors\":\"Gabriel Ferreira Barros, Bruno Pasqualotto Cavalar, Y. Kohayakawa, Guilherme Oliveira Mota, Tássio Naia\",\"doi\":\"10.1051/ro/2024090\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We investigate the threshold [[EQUATION]] for the Ramsey-type property [[EQUATION]], where [[EQUATION]] is the binomial random graph and [[EQUATION]] indicates that every orientation of the graph [[EQUATION]] contains the oriented graph [[EQUATION]] as a subdigraph. Similarly to the classical Ramsey setting, the upper bound [[EQUATION]] is known to hold for some constant [[EQUATION]], where [[EQUATION]] denotes the maximum 2-density of the underlying graph [[EQUATION]] of [[EQUATION]]. While this upper bound is indeed the threshold for some [[EQUATION]], this is not always the case. We obtain examples arising from rooted products of orientations of sparse graphs (such as forests, cycles and, more generally, subcubic [[EQUATION]]-free graphs) and arbitrarily rooted transitive triangles.\",\"PeriodicalId\":506995,\"journal\":{\"name\":\"RAIRO - Operations Research\",\"volume\":\"13 6\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-04-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"RAIRO - Operations Research\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1051/ro/2024090\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"RAIRO - Operations Research","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1051/ro/2024090","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Directed graphs with lower orientation Ramsey thresholds
We investigate the threshold [[EQUATION]] for the Ramsey-type property [[EQUATION]], where [[EQUATION]] is the binomial random graph and [[EQUATION]] indicates that every orientation of the graph [[EQUATION]] contains the oriented graph [[EQUATION]] as a subdigraph. Similarly to the classical Ramsey setting, the upper bound [[EQUATION]] is known to hold for some constant [[EQUATION]], where [[EQUATION]] denotes the maximum 2-density of the underlying graph [[EQUATION]] of [[EQUATION]]. While this upper bound is indeed the threshold for some [[EQUATION]], this is not always the case. We obtain examples arising from rooted products of orientations of sparse graphs (such as forests, cycles and, more generally, subcubic [[EQUATION]]-free graphs) and arbitrarily rooted transitive triangles.