Ribbon tableaux, Hall–Littlewood functions, quantum affine algebras, and unipotent varieties

Abstract

We introduce a new family of symmetric functions, which are q analogs of products of Schur functions, defined in terms of ribbon tableaux. These functions can be interpreted in terms of the Fock space representation ℱq of Uq(s𝔩n), and are related to Hall–Littlewood functions via the geometry of flag varieties. We present a series of conjectures, and prove them in special cases. The essential step in proving that these functions are actually symmetric consists in the calculation of a basis of highest weight vectors of ℱq using ribbon tableaux.