Double-loop algebras and the Fock space

The fermionic Fock space admits two different actions of the quantized enveloping algebra of $\hat\sln$> The first one is a q-deformation of the well-known level-one representation of the affine Lie algebra and the second one is a new level-zero action arising from solvable lattices models. In this paper we prove that these two constructions can be glued together to get a representation of a new object: the toridal quantum group. This representation involves some difference operatorators. It is due to the fact that the specialization at q=1 of the toroidal algebra is isomorphic to the enveloping algebra of the universal central extension of a current algebra over a quantum torus.