摘要
设A是图G的一个顶点子集，若对于任给u，v∈A有距离d（u,v）＞2，则称A是G的一个2-装填，G的最大2-装填的阶称为G的2-装填数，记为P2（G）。设γ（G）表示G的控制数。本文得到γ（G）＝P2（G）的图G的结构表征。
Let A be a subset of vertices of a graph G. A is said to be a 2-packing in G if the distance d（u, v）〉2 for any u, v ∈A. The 2 -packing number of G, denoted by P2（G）,is the order of a largest 2-packing in G. Let γ （G） denote the domination number of G. In this note, we obtain a structural characterization of graphs G with γ（G）=P2（G） as follows. A graph G satisfies γ（G）=P2（G） if and only if G contains a spanning forest F with each component being a star such that there is a largest 2-packing in F that is also a 2-packing in G.
关键词
图
控制数
2-装填数
Graph, domination number, 2-packing number.
