摘要
文章采用了类似Ji s等(2014)的方法,研究了树、单圈图、双圈图的改进的第二Zagreb指标,通过四个图变换(其中图变换1,2是严格增该指标的变换,图变换3,4是严格减该指标的变换)严格论证,分别得出了树、单圈图、双圈图的极大极小值.
In this paper, we will use the similar way （Ji S,2014） to study the trees, unicyclic and bicy- clic graphs with the second reformulated Zagreb indices, we strictly demonstrate by four graph operations （graph operation 1,2 which strictly increase this index and graph operation 3,4 which strictly decrease this in- dex ）, then we determine the maximum and minimum indices for the second reformulated Zagreb indices of trees, unicyclic and bicyclic graphs, respectively.
作者
秦忠芳
袁利
赵飚
QIN Zhong-fang YUAN Li ZHAO Biao(College of Mathematics and System Sciences, Xinjiang University, 830046,Urumqi, PR)
出处
《曲阜师范大学学报（自然科学版）》
CAS
2017年第4期15-20,共6页
Journal of Qufu Normal University(Natural Science)
关键词
改进的第二Zagreb指标
树
单圈图
双圈图
图变换
The second reformulated Zagreb index
trees
unicyclic graph
bicyclic graph
graph operation
