{"title":"从$$\\chi$$-有界性分离多项式$$\\chi$$-有界","authors":"Marcin Briański, James Davies, Bartosz Walczak","doi":"10.1007/s00493-023-00054-3","DOIUrl":null,"url":null,"abstract":"<p>Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function <span>\\(f:\\mathbb {N}\\rightarrow \\mathbb {N}\\cup \\{\\infty \\}\\)</span> with <span>\\(f(1)=1\\)</span> and <span>\\(f(n)\\geqslant \\left( {\\begin{array}{c}3n+1\\\\ 3\\end{array}}\\right) \\)</span>, we construct a hereditary class of graphs <span>\\({\\mathcal {G}}\\)</span> such that the maximum chromatic number of a graph in <span>\\({\\mathcal {G}}\\)</span> with clique number <i>n</i> is equal to <i>f</i>(<i>n</i>) for every <span>\\(n\\in \\mathbb {N}\\)</span>. In particular, we prove that there exist hereditary classes of graphs that are <span>\\(\\chi \\)</span>-bounded but not polynomially <span>\\(\\chi \\)</span>-bounded.</p>","PeriodicalId":50666,"journal":{"name":"Combinatorica","volume":"13 23","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"18","resultStr":"{\"title\":\"Separating Polynomial $$\\\\chi $$ -Boundedness from $$\\\\chi $$ -Boundedness\",\"authors\":\"Marcin Briański, James Davies, Bartosz Walczak\",\"doi\":\"10.1007/s00493-023-00054-3\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function <span>\\\\(f:\\\\mathbb {N}\\\\rightarrow \\\\mathbb {N}\\\\cup \\\\{\\\\infty \\\\}\\\\)</span> with <span>\\\\(f(1)=1\\\\)</span> and <span>\\\\(f(n)\\\\geqslant \\\\left( {\\\\begin{array}{c}3n+1\\\\\\\\ 3\\\\end{array}}\\\\right) \\\\)</span>, we construct a hereditary class of graphs <span>\\\\({\\\\mathcal {G}}\\\\)</span> such that the maximum chromatic number of a graph in <span>\\\\({\\\\mathcal {G}}\\\\)</span> with clique number <i>n</i> is equal to <i>f</i>(<i>n</i>) for every <span>\\\\(n\\\\in \\\\mathbb {N}\\\\)</span>. In particular, we prove that there exist hereditary classes of graphs that are <span>\\\\(\\\\chi \\\\)</span>-bounded but not polynomially <span>\\\\(\\\\chi \\\\)</span>-bounded.</p>\",\"PeriodicalId\":50666,\"journal\":{\"name\":\"Combinatorica\",\"volume\":\"13 23\",\"pages\":\"\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2023-08-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"18\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Combinatorica\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s00493-023-00054-3\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Combinatorica","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s00493-023-00054-3","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Separating Polynomial $$\chi $$ -Boundedness from $$\chi $$ -Boundedness
Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function \(f:\mathbb {N}\rightarrow \mathbb {N}\cup \{\infty \}\) with \(f(1)=1\) and \(f(n)\geqslant \left( {\begin{array}{c}3n+1\\ 3\end{array}}\right) \), we construct a hereditary class of graphs \({\mathcal {G}}\) such that the maximum chromatic number of a graph in \({\mathcal {G}}\) with clique number n is equal to f(n) for every \(n\in \mathbb {N}\). In particular, we prove that there exist hereditary classes of graphs that are \(\chi \)-bounded but not polynomially \(\chi \)-bounded.
期刊介绍:
COMBINATORICA publishes research papers in English in a variety of areas of combinatorics and the theory of computing, with particular emphasis on general techniques and unifying principles. Typical but not exclusive topics covered by COMBINATORICA are
- Combinatorial structures (graphs, hypergraphs, matroids, designs, permutation groups).
- Combinatorial optimization.
- Combinatorial aspects of geometry and number theory.
- Algorithms in combinatorics and related fields.
- Computational complexity theory.
- Randomization and explicit construction in combinatorics and algorithms.