International Journal of Mathematics and Mathematical Sciences
Volume 2007 (2007), Article ID 46851, 8 pages
Research Article

Nonderogatory Unicyclic Digraphs

Diego Bravo and Juan Rada

Departamento de Matemáticas, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela

Received 6 October 2006; Accepted 9 February 2007

Academic Editor: Dalibor Froncek

Copyright © 2007 Diego Bravo and Juan Rada. 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.


A digraph is nonderogatory if its characteristic polynomial and minimal polynomial are equal. We find a characterization of nonderogatory unicyclic digraphs in terms of Hamiltonicity conditions. An immediate consequence of this characterization ia that the complete product of difans and diwheels is nonderogatory.