Complete sets of functions for perturbations of Robertson-Walker cosmologies and spin 1 equations in Robertson-Walkertype spacetimes

Crucial to a knowledge of the perturbations of Robertson-Walker cosmological models are complete sets of functions with which to expand such perturbations. For the open Robertson-Walker cosmology an answer to this question is given. In addition some observations concerning explicit solution by separation of variables of wave equations for spin 1 in a Riemannian space having an infinitesimal line element of which the Robertson-Walker models are a special case are made.