MASSIMO PORRATI New York University: Strings on the AdS3 Wess-Zumino model are solvable 2D CFT so they are known exactly in the worldsheet. Their target space Virasoro algebra is represented by vertex operators. The Virasoro central extension is represented by an identity operator that should take the same value on all physical correlators, but it doesn't. I show how to resolve this problem by properly defining the holographic dictionary relating bulk string theory observables to correlators in the boundary CFT. 19/01/2016

DATA: 19-01-2016