Inflationary cosmology from STM theory of gravity

I study the power-law and de Sitter expansions for the universe during inflation from the STM theory of gravity. In a de Sitter expansion the additional dimension is related to the cosmological constant Lambda = 3/psi(2). I find from experimental data that the mass of the inflaton field is m(2) = 2/(3psi(2)). The interesting in this case is that the inflaton field fluctuations are related to the fifth coordinate. In power-law expansion, the fifth coordinate (psi) appears to be a dimensionless constant. Here, the psi-value depends on the initial conditions. I find the 5D line element for this inflationary expansion, which is a function of the classical component of the inflaton. But the more important result here obtained is that in both cases there is not dynamical compactification during inflation. (C) 2003 Elsevier Science B.V. All rights reserved.