{"title":"Embedding connected factorizations II","authors":"Amin Bahmanian , Anna Johnsen-Yu","doi":"10.1016/j.jctb.2025.03.003","DOIUrl":null,"url":null,"abstract":"<div><div>Let <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> be the complete <em>h</em>-uniform <em>n</em>-vertex hypergraph in which each edge is repeated <em>λ</em> times. For <span><math><mi>r</mi><mo>:</mo><mo>=</mo><mo>(</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>k</mi></mrow></msub><mo>)</mo></math></span>, a <em>(partial)</em> <strong>r</strong><em>-factorization</em> of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> is a partition of the edges of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> into factors <span><math><msub><mrow><mi>F</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span> such that each factor is spanning and the degree of all vertices in each <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> is (at most) <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>. Suppose that <span><math><mi>n</mi><mo>≥</mo><mo>(</mo><mi>h</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>(</mo><mn>2</mn><mi>m</mi><mo>−</mo><mn>1</mn><mo>)</mo></math></span>. We establish necessary and sufficient conditions that ensure a partial <strong>r</strong>-factorization of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>m</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> can be embedded in a connected <strong>r</strong>-factorization of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span>. Moreover, we prove a general result which leads to a complete characterization of partial <span><math><mo>(</mo><msub><mrow><mi>s</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>s</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>)</mo></math></span>-factorizations of <em>any</em> sub-hypergraph of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>m</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> in connected <strong>r</strong>-factorizations of <span><math><mi>λ</mi><msubsup><mrow><mi>K</mi></mrow><mrow><mi>n</mi></mrow><mrow><mi>h</mi></mrow></msubsup></math></span> so long as <em>q</em> meets a natural upper bound. These results can be seen as unified generalizations of many classical combinatorial results, and can also be restated as results on embedding partial symmetric latin hypercubes.</div></div>","PeriodicalId":54865,"journal":{"name":"Journal of Combinatorial Theory Series B","volume":"173 ","pages":"Pages 374-398"},"PeriodicalIF":1.2000,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Combinatorial Theory Series B","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0095895625000206","RegionNum":1,"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
Let be the complete h-uniform n-vertex hypergraph in which each edge is repeated λ times. For , a (partial)r-factorization of is a partition of the edges of into factors such that each factor is spanning and the degree of all vertices in each is (at most) . Suppose that . We establish necessary and sufficient conditions that ensure a partial r-factorization of can be embedded in a connected r-factorization of . Moreover, we prove a general result which leads to a complete characterization of partial -factorizations of any sub-hypergraph of in connected r-factorizations of so long as q meets a natural upper bound. These results can be seen as unified generalizations of many classical combinatorial results, and can also be restated as results on embedding partial symmetric latin hypercubes.
期刊介绍:
The Journal of Combinatorial Theory publishes original mathematical research dealing with theoretical and physical aspects of the study of finite and discrete structures in all branches of science. Series B is concerned primarily with graph theory and matroid theory and is a valuable tool for mathematicians and computer scientists.