Abelising the Virasoro operators

Abstract
The authors construct Abelised Virasoro operators, canonically conjugate to subsidiary constraints of the Virasoro algebra, within the context of the constrained Hamiltonian formalism. An auxiliary null vector is required for the construction. The original Virasoro operators re-emerge in a simple form from these Abelised operators, when proper care is taken to ensure Lorentz invariance, by treating the auxiliary null vector as a pure-gauge dynamical variable. They note a formal parallel between the Virasoro operators and the generators of Gauss' law in YM theories.