Constraining supersymmetric SO(10) models through cosmology

We study the impact of the symmetry-breaking patterns from supersymmetric SO(10) down to the standard model on the standard big-bang cosmology through the formation of topological defects. None of the models is consistent with the standard cosmology without invoking any mechanism to solve the monopole problem. For this purpose, we use a hybrid false vacuum inflationary scenario. Only two symmetry-breaking patterns are consistent with these topological considerations and with the actual data on the proton lifetime. {} 1995 The American Physical Society.