SIGNATURE CHANGE INDUCES COMPACTIFICATION

It is shown, using a FRW model with S-3 X S-6 as Spatial sections and a positive cosmological constant, that classical signature change implies a new compactification mechanism. The internal scale factor is of the order Lambda(-1/2), and the solutions are stable against small perturbations. In the case of compactified S-6, it is shown that the effective four-dimensional space-time metric has a Lorentzian signature, undergoes exponential inflation in S-3 and is unique. Speculations concerning relations to quantum cosmology and conceivable modifications are added.