Langlands duality for representations and quantum groups at a root of unity
arXiv:0902.1485 · doi:10.1007/s00220-010-0993-z
Abstract
We give a representation-theoretic interpretation of the Langlands character duality of Frenkel and Hernandez, and show that the "Langlands branching multiplicities" for symmetrizable Kac-Moody Lie algebras are equal to certain tensor product multiplicities. For finite type quantum groups, the connection with tensor products can be explained in terms of tilting modules.
Final version