Please use this identifier to cite or link to this item: https://scidar.kg.ac.rs/handle/123456789/9683
Title: Upper bound for the energy of strongly connected digraphs
Authors: Ayyaswamy S.
Balachandran S.
Gutman, Ivan
Issue Date: 2011
Abstract: The energy of a digraph D is dened as E(D), where z1, z2,..., zn are the (possibly complex) eigenvalues of D. We show that if D is a strongly connected digraph on n vertices, a arcs, and c2 closed walks of length two, such that Re(z1) ≥ (a + c2)=(2n) ≥ 1, then E(D) ≤ n(1 + √n)/2. Equality holds if and only if D is a directed strongly regular graph with parameters. This bound extends to digraphs an earlier result [J. H. Koolen, V. Moulton: Maximal energy graphs. Adv. Appl. Math., 26 (2001), 47-52], obtained for simple graphs.
URI: https://scidar.kg.ac.rs/handle/123456789/9683
Type: article
DOI: 10.2298/AADM101121030A
ISSN: 1452-8630
SCOPUS: 2-s2.0-79953303438
Appears in Collections:Faculty of Science, Kragujevac

Page views(s)

421

Downloads(s)

13

Files in This Item:
File Description SizeFormat 
10.2298-AADM101121030A.pdf189.99 kBAdobe PDFThumbnail
View/Open


This item is licensed under a Creative Commons License Creative Commons