  Implementing the requirement that a field theory be invariant under
Schwinger-Dyson BRST symmetry in the Hamiltonian formalism, we show the
equivalence between Hamiltonian and Lagrangian BRST-formalism at the path
integral level. The Lagrangian quantum master equation is derived as a direct
consequence of the Fradkin-Vilkovisky theorem in Hamiltonian BRST quantisation.
