Biquantization of Lie bialgebras

For any finite-dimensional Lie bialgebra g, we construct a bialgebra A(u,v) (g) over the ring C[u] [[v]], which quantizes simultaneously the universal enveloping bialgebra U (g), the bialgebra dual to U (g*), and the symmetri c bialgebra S (g). Following Turaev, we call A(u,v) (g) a biquantization of S (g). We show that the bialgebra A(u,v) (g*) quantizing U (g*), U (g*), a nd S (g*) is essentially dual to the bialgebra obtained from A(u,v) (g) by exchanging u and v. Thus, A(u,v) (g) contains all information about the qua ntization of g. Our construction extends Etingof and Kazhdan's one-variable quantization of U(g).