arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1909.08533math.CO
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复单位增益图的秩的独立数界

Bounds for the rank of a complex unit gain graph in terms of the independence number

Shengjie He, Rong-Xia Hao, Aimei Yu

摘要:

复单位增益图(或$\mathbb{T}$ -增益图)是由作为$(G, φ)$的基础图的图$G$、$\mathbb{T}= \{ z \in C:|z|=1 \} $和增益函数$φ: \overrightarrow{E} \rightarrow \mathbb{T}$组成的三元组$Φ=(G, \mathbb{T}, φ)$(简称$(G, φ)$),$\mathbb{T}= \{ z \in C:|z|=1 \} $是所有非零复数$\mathbb{C}^{\times}$的乘法群的子群,使得$φ(e_{ij})=φ(e_{ji})^{-1}=\overline{φ(e_{ji})}$。本文研究了阶为$n$的复单位增益图$(G, φ)$的秩、独立数和圈数之间的关系,证明了$2n-2c(G) \leq r(G, φ)+2α(G) \leq 2n$ .其中$r(G, φ)$、$α(G)$和$c(G)$分别是Hermite邻接矩阵$A(G, φ)$的秩、$G$的独立数和圈数。进一步刻画了复单位增益图达到下界的性质。

英文摘要:

A complex unit gain graph (or $\mathbb{T}$-gain graph) is a triple $Φ=(G, \mathbb{T}, φ)$ ($(G, φ)$ for short) consisting of a graph $G$ as the underlying graph of $(G, φ)$, $\mathbb{T}= \{ z \in C:|z|=1 \} $ is a subgroup of the multiplicative group of all nonzero complex numbers $\mathbb{C}^{\times}$ and a gain function $φ: \overrightarrow{E} \rightarrow \mathbb{T}$ such that $φ(e_{ij})=φ(e_{ji})^{-1}=\overline{φ(e_{ji})}$. In this paper, we investigate the relation among the rank, the independence number and the cyclomatic number of a complex unit gain graph $(G, φ)$ with order $n$, and prove that $2n-2c(G) \leq r(G, φ)+2α(G) \leq 2n$. Where $r(G, φ)$, $α(G)$ and $c(G)$ are the rank of the Hermitian adjacency matrix $A(G, φ)$, the independence number and the cyclomatic number of $G$, respectively. Furthermore, the properties of the complex unit gain graph that reaching the lower bound are characterized.

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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