Quotients of GL(n) by
finite subgroups can have radial algebraic automorphisms. More generally,
quotients of Π1sGL(ni) by (s − 1)-dimensional central subgroups can have
automorphisms not induced by automorphisms of ΠGL(ni). This paper
works out an explicit description of all their algebraic group automorphisms.
As a sample application, the normalizer of the GL(n)-action on Λr(kn) is
computed.