For a Lie group carrying a left invariant symplectic form certain Lagr
angian foliations are considered. We describe all left invariant (exac
t) symplectic structures on the affine group K(n) x GL(K(n)) for K=R o
r C. It is shown that for some of these structures there exists an exa
ct symplectic embeding of the real affine group onto an open subset of
the cotangent bundle of the Euclidean group R(n) x SO(n).