ABSTRACT
This chapter discusses some results connected with the effective action of composite fields in curved space-time. It considers the 0(iV)-model, the Gross Neveu model, and quantum electrodynamics with composite fermions in curved space-time. The chapter analyses renormalization group equations for the effective action of composite fields and construct gauge and the parameterization invariant effective action of composite fields. Composite fields play a very important role in many applications of quantum field theory. For example, if the elementary background field is equal to zero and the composite field is not equal to zero then dynamical generation of particle masses is possible. The chapter also discusses the renormalization group equations enabling one to investigate the asymptotic behaviour of the ea of elementary fields. The effective action of composite fields depends on the gauge condition as well as the effective action of elementary fields.
