DECELERATION PARAMETER Q(Z) IN 4D AND 5D GEOMETRIES, AND IMPLICATIONS OF GRAVITON MASS IN MIMICKING DARK ENERGY IN BOTH GEOMETRIES

The case for a four-dimensional graviton mass (non zero) influencing reacceleration of the universe in both four and five dimensions is stated, with particular emphasis on the question whether 4D and 5D geometries as given here yield new physical insight as to cosmological evolution. Both cases give equivalent reacceleration one billion years ago, which leads to the question whether other criteria can determine the relative benefits of adding additional dimensions to cosmology models.