SUPERSTRINGS FROM HAMILTONIAN REDUCTION

In any string theory there is a hidden, twisted superconformal symmetr y algebra, part of which is made up by the BRST current and the anti-g host. We investigate how this algebra can be systematically constructe d for strings with N - 2 supersymmetries, via quantum Hamiltonian redu ction of the Lie superalgebras osp(N/2). The motivation is to understa nd how one could systematically construct generalized string theories from superalgebras. We also briefly discuss the BRST algebra of the to pological string, which is a doubly twisted N = 4 superconformal algeb ra.