F-L:4ds @ Springer-Verlag 1988 Unification of coupling constants without a covering GUT

Abstract. We discuss the possibility of unification of gauge coupling constants of the standard model and its extensions at some high scale without he assump-tion of the existence of a covering GUT at that scale. In our analysis we examine (i) the standard model, (ii) its supersymmetric extension and (iii) an extension in which the spontaneous symmetry breaking is based on the condensation of high-colour fermions. The latter case is favoured for perturbative coupling constants unification while the supersymmetric extension of the standard model, with five families, is favoured for non-perturbative unification