A group-theoretical bound for the number of main eigenvalues of a graph

Authors
Cvetkovic, D Fowler, PW
Citation
D. Cvetkovic et Pw. Fowler, A group-theoretical bound for the number of main eigenvalues of a graph, J CHEM INF, 39(4), 1999, pp. 638-641
Citations number
12
Categorie Soggetti
Chemistry
Journal title
JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES
ISSN journal
00952338 → ACNP
Volume
39
Issue
4
Year of publication
1999
Pages
638 - 641
Database
ISI
SICI code
0095-2338(199907/08)39:4<638:AGBFTN>2.0.ZU;2-W
Abstract
An eigenvalue of a graph is called main if the corresponding eigenspace con tains an eigenvector in which the sum of coordinates is different from zero . It is proved that the number of main eigenvalues does not exceed the numb er of orbits (sets of vertices equivalent under the group of automorphisms of the graph).