classification of semisimple groups
For every semisimple group there is a normal subgroup![]()
of , (called the centerlesscompetely reducible radical
) which isomorphic
to a direct product
![]()
of nonabelian
simple groups
![]()
such that conjugation
![]()
on gives an injection into . Thus is isomorphic to asubgroup
![]()
of containing the inner automorphisms, and for every group isomorphicto a direct product of non-abelian
![]()
simple groups, every such subgroup is semisimple
.