It is well known that string theories are very rich in symmetry contents. I shall focus on massless sector of closed bosonic string. The effective action is known to be invariant under general coordinate transformations and under 'vector' gauge transformation of 2-form potential. For compactified closed string it admits nonabelian gauge invariance associated with massless gauge excitations. These symmetries are not exhibited by the worldsheet action which respects two-dimensional diffeo-morphism invariance. I shall show how the abovementioned target space local symmetries can be studied in Hamiltonian formulation of the theory in the worldsheet. There are some shortcomings and I shall propose possible resolutions.
Jnan Maharana (IOPB, Bhubaneswar): Ward Identities in String Theory
