Canonical transformations and quantization of singular Lagrangian systems

In this work we propose a method of quantization for models described by singular Lagrangians. A set of variables, suitable for the quantization, is obtained by means of a canonical transformation. The quantum theory is carried out by working in the complete phase space; in other words, we do not eliminate the variables corresponding to the second-class constraints, as suggested by Dirac. The expectation values of the constraints are required to be zero and the problem of the consistency of these conditions is studied.