Characterization of trees with Roman bondage number 1

• Main Authors: Fu-Tao Hu, Xing Wei Wang, Ning Li
• Format: Article
• Language: English
• Published: AIMS Press 2020-08-01
• Series: AIMS Mathematics
• Subjects: roman domination number; roman bondage number; tree
• Online Access: https://www.aimspress.com/article/10.3934/math.2020397/fulltext.html

Let $G=(V,E)$ be a simple undirected graph. A Roman dominating function on $G$ is a function $f: V\to \{0,1,2\}$ satisfying the condition that every vertex $u$ with $f(u)=0$ is adjacent to at least one vertex $v$ with $f(v)=2$. The weight of a Roman dominating function is the value $f(G)=\sum_{u\in V} f(u)$. The Roman domination number of $G$ is the minimum weight of a Roman dominating function on $G$. The Roman bondage number of a nonempty graph $G$ is the minimum number of edges whose removal results in a graph with the Roman domination number larger than that of $G$. Rad and Volkmann [9] proposed a problem that is to determine the trees $T$ with Roman bondage number $1$. In this paper, we characterize trees with Roman bondage number $1$.