Baryosynthesis and the origin of galaxies

Four cosmological models are examined in which it is possible, when discussing the origin of galaxies, to have both baryosynthesis and isothermal perturbations. Two of these models prove viable, namely, a universe which is initially dominated by large-scale inhomogeneous shear, and a universe which undergoes a de Sitter phase during the grand unified theory phase transition. It is also shown how to deduce new constraints on chaotic behaviour near the cosmological singularity. (U.K.)