设G为一简单连通图,则G的零阶广义Randic指数定义为Rα0(G)=∑ν∈V(G)dα(ν),其中d(v)为顶点ν的度数,α为非0和1的实数.图G称之为仙人掌图,如果G的每一块要么是一条边,要么是一个圈.本文研究有r个悬挂点仙人掌图的零阶广义Randic指数的界.L(n,r)、G(n,r)、H(n,r)、M(n,r)、N(n,r)分别表示一类图.当α〈0时,Rα0G)取得极大值当且仅当G∈M(n,r),Rα0取得极小值当且仅当G∈N(n,r);当0〈α〈1时,Rα0取得极大值当且仅当G∈N(n,r),Rα0取得极小值当且仅当G∈M(n,r);当α〉1时,Rα0取得极大值当且仅当G∈G(n,r),Rα0取得极小值当且仅当G∈H(n,r).
The zero-order general Randic index of a simple connected graph G is defined as R0α(G)=∑ν∈V(G)dα(ν),where d(ν) denotes the degree of ν,α is a given real number other than 0 and 1.A graph G is called a cactus if each block of G is either an edge or a cycle.In this paper,we present the sharp bounds of the zero-order general Randic index of cacti with r pendents.L(n,r),G(n,r),H(n,r),M(n,r)andN(n,r) denote some class of cacti respectvely.When α0,the maximal graph is in M(n,r) and the minimal graph is in N(n,r);when 0α1,the maximal graph is in N(n,r)and the minimal graph is in M(n,r);when α1,the maximal graph is in G(n,r)and the minimal graph is in H(n,r).