设G=(V,E)是一个图,一个函数f:V∪E→{-1,+}1,如果对每一个x∈E∪V,都有∑y∈Nt[x]f(y)≤0成立,则称f为图G的一个反符号全控制函数,其中Nt(x)表示G中与元素x相邻或相关联的元素之集,称为元素x的全邻域,Nt[x]=N(x)∪{x}为x的闭全邻域。规定图G的反符号全控制数定义为γrst(G)=max{∑x∈V∪Ef(x)f为图的反符号全控制函数}。得到了一般图的反符号全控制数的若干上界,并确定了圈Cn的反符号全控制数。
Let G=(V,E)be a graph,a function f:E→{-1,+1}is said to be a reverse signed total dominating function(RSTDF) of Gif ∑y∈Nt[x]f(y)≤0 holds for eachx∈V∪E,where Nt(x)is the set of all elements which are adjacent to x or are incident to x,and is called the total neighbourhood of x,Nt[x]=Nt(x)∪{x}is the closed one.The reverse signed total domination number of G is defined asγ′rst(G)=max{∑e∈V∪Ef(e)│f is a RSTDFofG}.In this paper,some upper bounds of the reverse signed total domination numbers of graphs are given,and determine the reverse signed total domination numbers of the cycles Cn.