Kd. Rothe et al., BRST COHOMOLOGY AND HILBERT-SPACES OF NON-ABELIAN MODELS IN THE DECOUPLED PATH-INTEGRAL FORMULATION, Annals of physics, 255(1), 1997, pp. 97-124
The existence of several nilpotent Noether charges in the decoupled fo
rmulation of two-dimensional gauge theories does not imply that all of
these are required to annihilate the physical states. We elucidate th
is matter in the context of simple quantum mechanical and field theore
tical models, where the structure of the Hilbert space is known. We pr
ovide a systematic procedure for deciding which of the BRST conditions
is to be imposed on the physical states in order to ensure the equiva
lence of the decoupled formulation to the original, coupled one. (C) 1
997 Academic Press.