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  • P-ISSN3059-0604
  • E-ISSN3059-1309
  • KCI

EXTREMAL CHEMICAL TREES WITH RESPECT TO HYPER-ZAGREB INDEX

Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics / Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics, (P)3059-0604; (E)3059-1309
2019, v.26 no.3, pp.177-188
https://doi.org/10.7468/jksmeb.2019.26.3.177
Ghalavand, Ali
Ashrafi, Ali Reza
Sharafdini, Reza
Ori, Ottorino

Abstract

Suppose G is a molecular graph with edge set E(G). The hyper-Zagreb index of G is defined as $HM(G)={\sum}_{uv{\in}E(G)}[deg_G(u)+deg_G(v)]^2$, where $deg_G(u)$ is the degree of a vertex u in G. In this paper, all chemical trees of order $n{\geq}12$ with the first twenty smallest hyper-Zagreb index are characterized.

keywords
extremal problems, chemical tree, hyper-Zagreb, graph operation

Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics