CONFORMAL-INVARIANCE IN CLASSICAL FIELD-THEORY

A geometric generalization of the first order Lagrangian formalism is used to analyze a conformal field theory for an arbitrary primary field. We require that the global conformal transformations are Noetherian symmetries and we prove that the action functional can be taken strictly invariant with respect to these transformations. In other words, there does not exist a ''Chem-Simons'' type Lagrangian for a conformally invariant Lagrangian theory.