定义在图G上的一个函数f:V(G)→{1,0,1},如果在任何一点的开领域的权和至少为1,则称,是一个全负控制函数(简记为(MTDF).对一个全负控制函数,而言,如果不存在一个全负控制函数g:V(G)→{-1,0,1},f≠g,对每个点v∈V(G),有g(v)≤f(v),则称,是极小的.一个MTDF f的权是指其所有点函数值的总和.图G的全负控制数是G的极小MTDF的最小权,而图G的上全负控制数是G的极小MTDF的最大权.本文主要研究这两个参数,得到它们的一些界的结论.
A function f:V(G)→{ -1,0,1 }defined on the vertices of a graph G is a minus total domination funating function (MTDF) if the sum of its function values over any open neighborhood is at one. A MTDF f is minimal if there does not exist a MTDF g: V(G)→{-1,0,1} ,f≠g,for which g(v)≤f(v) for every v∈V(G). The weight of a MTDF is the sum of its function values over all vertices. The minus total domination number of G is the minimum weight of a MTDF of G, while the upper minus total domination number of G is the maximum weight of a minimal MTDF on G. This paper studies these two parameters. In particular, it presents lower bounds on the study total domination number and upper bounds on the upper minus total domination number of a graph.