Let K be a field and let X be an abelian variety over K. The group Aut
X of K-automorphisms of X acts in a natural way on the set of abelian
subvarieties of X that are defined over K. In this paper it is proved
that the number of orbits is finite. The proof makes use of a finiten
ess result about semisimple algebras. (C) 1996 Academic Press, Inc.