带有针状分支顶点的诱导细分区

IF 1 3区 数学 Q1 MATHEMATICS European Journal of Combinatorics Pub Date : 2024-09-22 DOI:10.1016/j.ejc.2024.104072
Sepehr Hajebi
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Then either <span><math><mi>G</mi></math></span> contains <span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span> or <span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>t</mi><mo>,</mo><mi>t</mi></mrow></msub></math></span> as an induced subgraph, or there is an induced subgraph <span><math><mi>J</mi></math></span> of <span><math><mi>G</mi></math></span> isomorphic to a proper <span><math><mrow><mo>(</mo><mo>≤</mo><mi>r</mi><mo>)</mo></mrow></math></span>-subdivision of <span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> such that every branch vertex of <span><math><mi>J</mi></math></span> is a branch vertex of <span><math><mi>H</mi></math></span>. This answers in the affirmative a question of Lozin and Razgon. 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引用次数: 0

摘要

我们证明,对于所有 r∈N∪{0} 和 s,t∈N,存在具有以下性质的 Ω=Ω(r,s,t)∈N。设 G 是图,设 H 是 G 的子图,与 KΩ 的(≤r)细分同构。那么要么 G 包含作为诱导子图的 Kt 或 Kt,t,要么 G 的诱导子图 J 与 Ks 的适当 (≤r)- 细分同构,使得 J 的每个分支顶点都是 H 的分支顶点。事实上,我们证明了分支顶点和它们之间对应于细分边的路径都可以保留。
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Induced subdivisions with pinned branch vertices
We prove that for all rN{0} and s,tN, there exists Ω=Ω(r,s,t)N with the following property. Let G be a graph and let H be a subgraph of G isomorphic to a (r)-subdivision of KΩ. Then either G contains Kt or Kt,t as an induced subgraph, or there is an induced subgraph J of G isomorphic to a proper (r)-subdivision of Ks such that every branch vertex of J is a branch vertex of H. This answers in the affirmative a question of Lozin and Razgon. In fact, we show that both the branch vertices and the paths corresponding to the subdivided edges between them can be preserved.
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来源期刊
CiteScore
2.10
自引率
10.00%
发文量
124
审稿时长
4-8 weeks
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.
期刊最新文献
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