Using the generalized Hamiltonian method of Batalin, Fradkin and Vilkovsky we develop the BRST formalism for the bosonic string on AdS5×S formulated as principal chiral model. Then we show that the monodromy matrix and non-local charges are BRST invariant.

We revisit Khudaverdian’s geometric construction of an odd nilpotent operator ∆E that sends semidensities to semidensities on an antisymplectic manifold. We find a local formula for the ∆E operator in arbitrary coordinates and we discuss its connection to Batalin-Vilkovisky quantization. MCS number(s): 53A55; 58A50; 58C50; 81T70.

Following systematically the generalized Hamiltonian approach of Batalin and Fradkin, we demonstrate the equivalence of a self-dual model with the Maxwell-Chern-Simons theory by embedding the former second-class theory into a rst-class theory. On sabbatical leave from S.N. Bose National Centre for Basic Sciences, DB-17, Sec 1, Salt Lake, Calcutta-700064, India