SHANDONG SCIENCE ›› 2016, Vol. 29 ›› Issue (1): 83-86.doi: 10.3976/j.issn.1002-4026.2016.01.014

• Other Research Article • Previous Articles     Next Articles

Harmonic index of tree and unicyclic graphs

Wang Xiao   

  1. School of Mathematics and Computer Engineering, Shangluo University, Shangluo 726000, China
  • Received:2015-04-23 Online:2016-02-20 Published:2016-02-20

Abstract:

We obtain two lemmas for harmonic index of graphs through the transforms changing leaf numbers.We further prove the sharp bounds for harmonic index of tree and unicyclic graphs with fixed order.We also present the corresponding extremal graphs.

Key words: tree graphs, harmonic index, unicyclic graphs

CLC Number: 

  • O157.5