arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2109.01809math.CO
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线性森林的广义Turán数

Generalized Turán number for linear forests

Xiutao Zhu, Yaojun Chen

摘要:

广义Turán数$ex(n,K_s,H)$被定义为完全图$K_s$在任意$n$顶点上的无$H$图中的最大拷贝数.令$F$是由$\ell_1,\ell_2,...,\ell_k$阶的$k$路径组成的线性森林。本文通过刻画最小度大的无$F$图的结构,确定了除部分$\ell_i=3$外的$n=Ω\left(|F|^s\right)$和$k\geq 2$的$ex(n,K_s,F)$值,以及相应的极图.我们的结果的$s=2$改进了Bushmann and Kettle(2011)和Lidickhmann et al.(2013)关于线性森林的经典Turán数的一些结果。

英文摘要:

The generalized Turán number $ex(n,K_s,H)$ is defined to be the maximum number of copies of a complete graph $K_s$ in any $H$-free graph on $n$ vertices. Let $F$ be a linear forest consisting of $k$ paths of orders $\ell_1,\ell_2,...,\ell_k$. In this paper, by characterizing the structure of the $F$-free graph with large minimum degree, we determine the value of $ex(n,K_s,F)$ for $n=Ω\left(|F|^s\right)$ and $k\geq 2$ except some $\ell_i=3$, and the corresponding extremal graphs. The special case when $s=2$ of our result improves some results of Bushaw and Kettle (2011) and Lidický et al. (2013) on the classical Turán number for linear forests.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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