%0 Journal Article
%T Nonderogatory directed windmills
%A RADA
%A JUAN
%J Revista Colombiana de Matem¨¢ticas
%D 2008
%I Universidad Nacional de Colombia and Sociedad Colombiana de Matem¨¢ticas
%X a directed graph g is nonderogatory if its adjacency matrix a is nonderogatory, i.e., the characteristic polynomial of a is equal to the minimal polynomial of a. given integers r¡Ý 2 and h¡Ý 3, a directed windmill mh(r) is a directed graph obtained by coalescing r dicycles of length h in one vertex. in this article we solve a conjecture proposed by gan and koo ([3]): mh(r) is nonderogatory if and only if r=2.
%K nonderogatory matrix
%K characteristic polynomial of directedgraphs
%K directed windmills.
%U http://www.scielo.org.co/scielo.php?script=sci_abstract&pid=S0034-74262008000100005&lng=en&nrm=iso&tlng=en