INHOMOGENEOUS MODEL WITH A COSMOLOGICAL CONSTANT

We extend an earlier work of Tosa to include the effects of inhomogene ity in the cosmological evolution in Kaluza-Klein spacetime with a cos mological constant. It is observed that the presence of inhomogeneity drastically changes the evolutionary scenario such that our five-dimen sional spacetime admits inflation in three-space and dimensional reduc tion of the extra space. This result is at variance with an earlier co nclusion of Tosa for homogeneous models that only a negative cosmologi cal constant with more than one extra spatial dimension can provide in flation of three-space and a small size of the extra one. The model al so seems to suggest an alterative mechanism pointing to a smooth trans ition from a primordial, multidimensional inhomogeneous phase to a fou r-dimensional homogeneous one.