arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0709.3140math.CO
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图的秩、色数与能量的关系

Some Relations between Rank, Chromatic Number and Energy of Graphs

S. Akbari, E. Ghorbani, S. Zare

摘要:

图$G$的能量,记为$E(G)$,定义为$G$的所有特征值的绝对值之和。设$G$是阶为$n$的图,${\rm rank}(G)$是$G$的邻接矩阵的秩.本文用$E(G)={\rm rank}(G)$刻画了所有图.在其他结果中,我们发现,除了少数几个家庭的图,$E(G)\geq 2\max(χ(G), n-χ(\bar{G}))$,其中$n$是$G$的顶点数,$\bar{G}$和$χ(G)$是补和色数的$G$,分别。此外,还给出了$E(G)$关于${\rm rank}(G)$的新的下界.

英文摘要:

The energy of a graph $G$, denoted by $E(G)$, is defined as the sum of the absolute values of all eigenvalues of $G$. Let $G$ be a graph of order $n$ and ${\rm rank}(G)$ be the rank of the adjacency matrix of $G$. In this paper we characterize all graphs with $E(G)={\rm rank}(G)$. Among other results we show that apart from a few families of graphs, $E(G)\geq 2\max(χ(G), n-χ(\bar{G}))$, where $n$ is the number of vertices of $G$, $\bar{G}$ and $χ(G)$ are the complement and the chromatic number of $G$, respectively. Moreover some new lower bounds for $E(G)$ in terms of ${\rm rank}(G)$ are given.

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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