Cosmology with Two Compactification Scales

We consider a(4+d)-dimensional spacetime broken up into a(4-n)-dimensional Minkowski spacetime(where n goes from 1 to 3)and a compact(n+d)-dimensional manifold.At the present time the n compactification radii are of the order of the Universe size,while the other d compactification radii are of the order of the Plancklength.