{"title":"Matching Stability for 3-Partite 3-Uniform Hypergraphs","authors":"Hongliang Lu, Xinxin Ma","doi":"10.1002/jgt.70089","DOIUrl":null,"url":null,"abstract":"<div>\n \n <p>Let <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>n</mi>\n \n <mo>,</mo>\n \n <mi>k</mi>\n \n <mo>,</mo>\n \n <mi>s</mi>\n </mrow>\n </mrow>\n </semantics></math> be three integers such that <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>k</mi>\n \n <mo>≥</mo>\n \n <mn>2</mn>\n </mrow>\n </mrow>\n </semantics></math> and <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>n</mi>\n \n <mo>≥</mo>\n \n <mi>s</mi>\n \n <mo>≥</mo>\n \n <mn>1</mn>\n </mrow>\n </mrow>\n </semantics></math>. Let <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>H</mi>\n </mrow>\n </mrow>\n </semantics></math> be a <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>k</mi>\n </mrow>\n </mrow>\n </semantics></math>-partite <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>k</mi>\n </mrow>\n </mrow>\n </semantics></math>-uniform hypergraph with <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>n</mi>\n </mrow>\n </mrow>\n </semantics></math> vertices in each class. Aharoni (2017) showed that if <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>e</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>H</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>></mo>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>s</mi>\n \n <mo>−</mo>\n \n <mn>1</mn>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n \n <msup>\n <mi>n</mi>\n \n <mrow>\n <mi>k</mi>\n \n <mo>−</mo>\n \n <mn>1</mn>\n </mrow>\n </msup>\n </mrow>\n </mrow>\n </semantics></math>, then <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>H</mi>\n </mrow>\n </mrow>\n </semantics></math> has a matching of size <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>s</mi>\n </mrow>\n </mrow>\n </semantics></math>. In this paper, we give a stability result for 3-partite 3-uniform hypergraphs: if <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> is a 3-partite 3-uniform hypergraph with <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>n</mi>\n \n <mo>≥</mo>\n \n <mn>162</mn>\n </mrow>\n </mrow>\n </semantics></math> vertices in each class, <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>e</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>G</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>≥</mo>\n \n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mi>s</mi>\n \n <mo>−</mo>\n \n <mn>1</mn>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n \n <msup>\n <mi>n</mi>\n \n <mn>2</mn>\n </msup>\n \n <mo>+</mo>\n \n <mn>3</mn>\n \n <mi>n</mi>\n \n <mo>−</mo>\n \n <mi>s</mi>\n </mrow>\n </mrow>\n </semantics></math> and <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> contains no matching of size <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>s</mi>\n \n <mo>+</mo>\n \n <mn>1</mn>\n </mrow>\n </mrow>\n </semantics></math>, then <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> has a vertex cover of size <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>s</mi>\n </mrow>\n </mrow>\n </semantics></math>. Our bound is also tight.</p>\n </div>","PeriodicalId":16014,"journal":{"name":"Journal of Graph Theory","volume":"113 4","pages":"650-662"},"PeriodicalIF":1.0000,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Graph Theory","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jgt.70089","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/6/19 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Let be three integers such that and . Let be a -partite -uniform hypergraph with vertices in each class. Aharoni (2017) showed that if , then has a matching of size . In this paper, we give a stability result for 3-partite 3-uniform hypergraphs: if is a 3-partite 3-uniform hypergraph with vertices in each class, and contains no matching of size , then has a vertex cover of size . Our bound is also tight.
期刊介绍:
The Journal of Graph Theory is devoted to a variety of topics in graph theory, such as structural results about graphs, graph algorithms with theoretical emphasis, and discrete optimization on graphs. The scope of the journal also includes related areas in combinatorics and the interaction of graph theory with other mathematical sciences.
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