PROJECTION OPERATOR APPROACH TO CONSTRAINED SYSTEMS

Recently, having reconsidered the reproducing kernel for gauge-invaria nt states which involves the projection operator onto the reduced Hilb ert space of physical states, John Klauder has shown how the phase spa ce coherent state path integral quantization of constrained systems av oids any gauge-fixing conditions, and leads to a specific measure for the integration over Lagrange multipliers. Here, it is pointed out tha t independently of the coherent state formulation, this approach is al so devoid of any Gribov problems and always provides for an effectivel y admissible integration over all gauge orbits of gauge-invariant syst ems. This important aspect of Klauder's reappraisal of the physical re producing kernel is explicitly confirmed by two simple examples.