概稳定一般Kneser超图的色数

IF 0.4 Q4 MATHEMATICS, APPLIED
A. Jafari
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引用次数: 1

摘要

设$n\ge 1$和$s\ge 1$为整数。$[n]=\{1,\dots,n\}$的一个几乎$s$稳定的子集$A$是这样一个子集:对于任意两个不同的元素$i, j\in A$,其中一个具有$|i-j|\ge s$。对于$[n]$和$r\ge 2$的子集$\cal F$,对于$r$ -均匀Kneser超图$\mbox{KG}^r({\cal F})$的色数,其顶点集为$\cal F$,其边集为$\cal F$的对向不相交元素的$\{A_1,\dots, A_r\}$的集合,已经在文献中得到了广泛的研究,Abyazi Sani和Alishahi能够根据可等价的$r$ -可色性缺陷给出它的下界。$\mbox{ecd}^r({\cal F})$。本文修正了关于$[n]$的所有$k$ -子集的特殊族的Chen方法,给出了关于$\mbox{ecd}^s({\cal F})$的概稳定一般Kneser超图$\mbox{KG}^r({\cal F}_s)$的色数的下界。这里${\cal F}_s$是$\cal F$中几乎$s$稳定元素的集合。我们还提出了对莫尼耶猜想的推广。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
On the chromatic number of almost stable general Kneser hypergraphs
Let $n\ge 1$ and $s\ge 1$ be integers. An almost $s$-stable subset $A$ of $[n]=\{1,\dots,n\}$ is a subset such that for any two distinct elements $i, j\in A$, one has $|i-j|\ge s$. For a family $\cal F$ of subsets in $[n]$ and $r\ge 2$, the chromatic number of the $r$-uniform Kneser hypergraph $\mbox{KG}^r({\cal F})$, whose vertex set is $\cal F$ and whose edges set is the set of $\{A_1,\dots, A_r\}$ of pairwise disjoint elements of $\cal F$, has been studied extensively in the literature and Abyazi Sani and Alishahi were able to give a lower bound for it in terms of the equatable $r$-colorability defect, $\mbox{ecd}^r({\cal F})$. In this article, the methods of Chen for the special family of all $k$-subsets of $[n]$, are modified to give lower bounds for the chromatic number of almost stable general Kneser hypergraph $\mbox{KG}^r({\cal F}_s)$ in terms of $\mbox{ecd}^s({\cal F})$. Here ${\cal F}_s$ is he collection of almost $s$-stable elements of $\cal F$. We also, propose a generalization of conjecture of Meunier.
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来源期刊
Journal of Combinatorics
Journal of Combinatorics MATHEMATICS, APPLIED-
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