  The conformal affine sl(2) Toda model coupled to matter field is treated as a
constrained system in the context of Faddeev-Jackiw and the (constrained)
symplectic schemes. We recover from this theory either, the sine-Gordon or the
massive Thirring model, through a process of Hamiltonian reduction, considering
the equivalence of the Noether and topological currrents as a constraint and
gauge fixing the conformal symmetry.
