HOMOGENEOUS ANISOTROPIC COSMOLOGICAL MODELS WITH VARIABLE GRAVITATIONAL AND COSMOLOGICAL CONSTANTS

The Einstein field equations with perfect fluid source and variable LA MBDA and G for Bianchi-type universes are studied under the assumption of a power-law time variation of the expansion factor, achieved via a suitable power-law assumption for the Hubble parameter suggested by M . S. Berman. All the models have a power-law variation of pressure and density and are singular at the epoch t = 0. The variation of G(t) as 1/t and LAMBDA(t) as 1/t2 is consistent with these models.