We show how a theorem of Sullivan provides a precise mathematical statement
of a 3D holographic principle, that is, the hyperbolic structure of a cert
ain class of 3D manifolds is completely determined in terms of the correspo
nding Teichmuller space of the boundary. We explore the consequences of thi
s theorem in the context of the Euclidean Banados-Teitelboim-Zanelli black
hole in three dimensions. [S0031-9007(99)09228-5].