Inflation and broken Lorentz symmetry in the very early universe

It is shown that an inflationary phase of accelerated expansion can be arranged even if the total energy is not dominated by the contribution of the vacuum background, provided that at some very early epoch the gravitational interactions are described by a theory which is not locally Lorentz invariant. It is also suggested that this additional mechanism for producing inflation could be used to solve some problems of the standard inflationary scenario. (orig.)