  The discriminant power of centrality indices for the degree, eigenvector,
closeness, betweenness and subgraph centrality is analyzed. It is defined by
the number of graphs for which the standard deviation of the centrality of its
nodes is zero. On the basis of empirical analysis it is concluded that the
subgraph centrality displays better discriminant power than the rest of
centralities. We also propose some new conjectures about the types of graphs
for which the subgraph centrality does not discriminate among nonequivalent
nodes.
