Journal of Inequalities and Applications
Volume 2010 (2010), Article ID 904196, 11 pages
Research Article

A New Like Quantity Based on “Estrada Index”

Department of Mathematics, Science Faculty, Selçuk University, 42075 Konya, Turkey

Received 12 February 2010; Accepted 16 March 2010

Academic Editor: Martin Bohner

Copyright © 2010 A. Dilek Güngör. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We first define a new Laplacian spectrum based on Estrada index, namely, Laplacian Estrada-like invariant, LEEL, and two new Estrada index-like quantities, denoted by S and EEX, respectively, that are generalized versions of the Estrada index. After that, we obtain some lower and upper bounds for LEEL, S, and EEX.