ON A GAUGE-INVARIANT QUANTUM FORMULATION FOR NON-GAUGE CLASSICAL-THEORY

We propose a method of constructing a gauge invariant canonical formul ation for non-gauge classical theory which depends on a set of paramet ers. Requirement of closure for algebra of operators generating quantu m gauge transformations leads to restrictions on parameters of the the ory. This approach is then applied for illustration to bosonic string theory coupled to background tachyonic field. It is shown that within the proposed canonical formulation the known mass-shell condition for tachyon is produced.