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The Second Geometric-Arithmetic Index For Trees and Unicyclic Graphs
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نویسنده
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Dehgardi Nasrin ,Aram Hamideh ,Khodkar Abdollah
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منبع
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Iranian Journal Of Mathematical Chemistry - 2018 - دوره : 9 - شماره : 4 - صفحه:279 -287
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چکیده
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Let $g$ be a finite and simple graph with edge set $e(g)$. the second geometricarithmetic index is defined as $ga_2(g)=sum_{uvin e(g)}frac{2sqrt{n_un_v}}{n_u+n_v}$, where $n_u$ denotes the number of vertices in $g$ lying closer to $u$ than to $v$. in this paper we find a sharp upper bound for $ga_2(t)$, where $t$ is tree, in terms of the order and maximum degree of the tree. we also find a sharp upper bound for $ga_2(g)$, where $g$ is a unicyclic graph, in terms of the order, maximum degree and girth of $g$. in addition, we characterize the trees and unicyclic graphs which achieve the upper bounds.
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کلیدواژه
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Second Geometric-Arithmetic Index ,Trees ,Unicyclic Graphs
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آدرس
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Sirjan University Of Technology, Department Of Mathematics And Computer Science, ایران, Islamic Azad University, Khoy Branch, Gareziaeddin Center, Department Of Mathematics, ایران, University Of West Georgia, Department Of Mathematics, Usa
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پست الکترونیکی
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akhodkar@westga.edu
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Authors
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