On ‎c‎omputing the general Narumi-Katayama index of some ‎graphs

الموضوعات : مجله بین المللی ریاضیات صنعتی

S. Z. Aghamohammadi‎ ¹

1 - Department of Mathematics, Eslamshahr Branch, Islamic Azad University, Tehran, Iran.

تاريخ الإرسال : 10 الجمعة , ربيع الثاني, 1436 تاريخ التأكيد : 10 الجمعة , ربيع الثاني, 1436 تاريخ الإصدار : 10 الخميس , ربيع الأول, 1436

الکلمات المفتاحية: Narumi-Katayama index, ‎ ‎Molecular graph, Clique number, Independent number, ‎Dendrimers.‎,

ملخص المقالة :

‎The Narumi-Katayama index was the first topological index defined‎ ‎by the product of some graph theoretical quantities‎. ‎Let $G$ be a ‎simple graph with vertex set $V = \{v_1,\ldots‎, ‎v_n \}$ and $d(v)$ be‎ ‎the degree of vertex $v$ in the graph $G$‎. ‎The Narumi-Katayama ‎index is defined as $NK(G) = \prod_{v\in V}d(v)$‎. ‎In this paper,‎ ‎the Narumi-Katayama index is generalized using a $n$-vector $x$‎ ‎and it is denoted by $GNK(G‎, ‎x)$ for a graph $G$‎. ‎Then‎, ‎we obtain ‎some bounds for $GNK$ index of a graph $G$ by terms of clique‎ ‎number and independent number of $G$‎. ‎Also we compute the $GNK$ ‎index of splice and link of two graphs‎. ‎Finally‎, ‎we use from our‎ ‎results to compute the $GNK$ index of a class of ‎dendrimers.