By using the Hamilton-Jacobi [HJ] framework the three dimensional Palatini theory plus a Chern-Simons term [PCS] is analyzed. We report the complete set of HJ Hamiltonians and a generalized HJ differential from which all symmetries of the theory are identified. Moreover, we show that in spite of PCS Lagrangian produces Einstein's equations, the generalized HJ brackets depend on a Barbero-Immirzi like parameter. In addition we complete our study by performing a canonical covariant analysis, and we construct a closed and gauge invariant two form that encodes the symplectic geometry of the covariant phase space. PACS numbers: 98.80.-k,98.80.Cq
I. INTRODUCTIONNowadays, the analysis of singular systems has been the cornerstone for studying all fundamental forces in nature. From the standard model, string theory, to canonical gravity and Loop Quantum Gravity there is a big effort for understanding the underlying symmetries of these systems [1][2][3][4][5]. In fact, these forces expose symmetries and it is mandatory to perform the study of these symmetries by using alternative frameworks beyond standard classical mechanics. In this respect, we can cite several approaches such as the Dirac-Bergman, Faddeev-Jackiw, Canonical Covariant and the Hamilton-Jacobi methods . The Dirac approach allows us to identify the constraints of singular systems, which are classified into first class and second class. The formed are generators of the gauge symmetry and the latter are used for constructing the Dirac brackets of the theory; with the constraints at hand the symmetries of the theory can be identified. Nonetheless, the classification between the constraints into first or second class is a difficult task, and alternative approaches can be required. In this respect, the Faddeev-Jackiw framework allows the construction of a symplectic tensor from which the symmetries of the theory can be identified. In the FJ framework it is not necessary to perform the classification of the constraints as in Dirac's method is done; for gauge systems in order to obtain the symplectic tensor it is necessary fixing the gauge, and this fact could complicate the analysis. On the other hand, the canonical covariant method is a symplectic approach based on the construction of a closed and gauge invariant symplectic two form. From the * Electronic address: aescalan@ifuap.buap.mx † Electronic address: jpantoja@ifuap.buap.mx