  By applying the Faddeev-Jackiw symplectic approach we systematically show
that both the local gauge symmetry and the constraint structure of
topologically massive gravity with a cosmological constant $\Lambda$, elegantly
encoded in the zero-modes of the symplectic matrix, can be identified.
Thereafter, via an appropriate partial gauge-fixing procedure, the time gauge,
we calculate the quantization bracket structure (generalized Faddeev-Jackiw
brackets) for the dynamic variables and confirm that the number of physical
degrees of freedom is one. This approach provides an alternative to explore the
dynamical content of massive gravity models.
