Invariant solutions of Liouville's equation in Robertson-Walker space- times
We find all solutions of Liouville's equation in Robertson-Walker space- times that are either spatially homogeneous or isotropic or both. Some of these solutions depend on constants of motion that are not generated by Killing vectors. We indicate how these solutions may be used to find Einstein-Liouville solutions.
scientific article; zbMATH DE number 4028357