Dispersive Friedmann universes and synchronization

Abstract We introduce consideration of dispersive aspects standard perfect fluid Friedmann cosmology and study the new qualitative behaviours cosmological solutions that emerge as parameter changes zero eigenvalues appear in linear part equations. find due to their insufficient degeneracy, Milne, flat, Einstein-static, de Sitter cannot properly bifurcate. However, versions Milne flat universes contained versal unfolding equations possess novel long-term properties not met counterparts. apply these results horizon problem show unlike hyperbolic versions, completely synchronize future, hence offering a solution homogeneity, isotropy, causal connectedness puzzles.