Winding Strings in AdS_3

Correlation functions of one unit spectral flowed states in string theory on AdS_3 are considered. We present the modified Knizhnik-Zamolodchikov and null vector equations to be satisfied by amplitudes containing states in winding sector one and study their solution corresponding to the four point function including one w=1 field. We compute the three point function involving two one unit spectral flowed operators and find expressions for amplitudes of three w=1 states satisfying certain particular relations among the spins of the fields. Several consistency checks are performed.Comment: 35 pages. v2. Important additions: one more author, complete results for the 3-point function with two w=1 states and new section with computation of 4-point function with one w=1 state. Acknowledgments and references modifie