【摘要】 图G=(V,E)的每个顶点控制它的闭邻域的每个顶点.S是一个顶点子集合,如果G的每一个顶点至少被S中的两个顶点控制,则称S是G的一个双控制集.把双控制集的最小基数称为双控制数,记为dd(G).本文探讨了双控制数和其它控制参数的一些新关系,推广了[1]的一些结果.并且给出了双控制数的Nordhaus-Gaddum类型的结果.更多还原

【Abstract】 Each vertex of a graph G = (V, E) is said to dominate every vertex in its closed neighborhood. A set S(?)V is a double dominating set for G if each vertex in V is dominated by at least two vertices in S. The smallest cardinality of a double dominating set is called the double dominating number dd(G). In this paper, new relationships between dd(G) and other domination parameters are explored and some results of [1] are extended. Furthermore, we give the Nordhaus-Gaddum-type results for double dominating number.更多还原