Title of article :
A ‎note‎ ‎on‎ ‎the‎ ‎r‎e-defined third Zagreb index of trees
Author/Authors :
Dehgardi ، Nasrin Department of Mathematics and Computer Science - Sirjan University of Technology
From page :
539
To page :
545
Abstract :
For a graph $\Gamma$‎, ‎the re-defined third Zagreb index is defined as $$ReZG_3(\Gamma)=\sum_{ab\in E(\Gamma)}\deg_\Gamma(a) ‎\deg_\Gamma(b)\Big(‎\deg_\Gamma(a)+‎\deg_\Gamma(b)\Big)‎‎,$$‎‎where $\deg_\Gamma(a)$ is the degree of‎ ‎vertex $a$‎. ‎We prove for any tree $T$ with $n$ vertices and maximum degree $\Delta$‎, ‎‎$ReZG_3(T)\geq‎16n+\Delta^3+2\Delta^2-13\Delta-26$ ‎when ‎‎$‎\Delta n-1‎$ ‎and‎ $ReZG_3(T)=‎n\Delta^2+n\Delta-\Delta^2-\Delta$ ‎when ‎‎$‎\Delta=n-1‎$. ‎Also we determine the corresponding extremal trees‎. ‎‎
Keywords :
Zagreb ‎ indices , ‎ re-defined third Zagreb index , ‎ ‎ trees
Journal title :
Communications in Combinatorics and Optimization
Journal title :
Communications in Combinatorics and Optimization
Record number :
2780619
Link To Document :
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