ADMISSIBLE GAUGES FOR CONSTRAINED SYSTEMS

Gauge-fixing and gaugeless methods for reducing the phase space in gen eralized Hamiltonian dynamics are compared with the aim to define the class of admissible gauges. In the gaugeless approach, the reduced pha se space of a Hamiltonian system with first class constraints is const ructed locally, without any gauge fixing, using the following procedur e: Abelianization of constraints with a subsequent canonical transform ation so that some of the new momenta are equal to the new Abelian con straints. As a result, the corresponding conjugate coordinates are ign orable (nonphysical) while the remaining canonical pairs correspond to the true dynamical variables. This representation of the phase space prompts the definition of the subclass of admissible gauges, canonical gauges, as functions depending only on the ignorable coordinates. A p ractical method to determine the canonical gauge is proposed.