The second-minimum Wiener index of cacti with given cycles

Autor: G. C. Keerthi Vasan, Selvaraj Balachandran, Hanyuan Deng
Rok vydání: 2020
Předmět:
Zdroj: Asian-European Journal of Mathematics. 14:2150039
ISSN: 1793-7183
1793-5571
DOI: 10.1142/s179355712150039x
Popis: The Wiener index [Formula: see text] of a connected graph [Formula: see text] is the sum of distances between all pairs of vertices of [Formula: see text]. A connected graph [Formula: see text] is said to be a cactus if each of its blocks is either a cycle or an edge. Let [Formula: see text] be the set of all [Formula: see text]-vertex cacti containing exactly [Formula: see text] cycles. Liu and Lu (2007) determined the unique graph in [Formula: see text] with the minimum Wiener index. Gutman, Li and Wei (2017) determined the unique graph in [Formula: see text] with maximum Wiener index. In this paper, we present the second-minimum Wiener index of graphs in [Formula: see text] and identify the corresponding extremal graphs, which solve partially the problem proposed by Gutman et al. [Cacti with [Formula: see text]-vertices and [Formula: see text] cycles having extremal Wiener index, Discrete Appl. Math. 232 (2017) 189–200] in 2017.
Databáze: OpenAIRE