In this paper, we extend the Drinfeld current realization of quantum affine algebras Uq(ĝ) and of the Yangians in several directions: we construct current operators for non-simple roots of g, define a new braid group action in terms of the current operators and describe the universal R-matrix for the corresponding “Drinfeld” comultiplication in the form of infinite product and in the form of ce...

The aim of this paper is to introduce the quantum analogues of torsors for a compact quantum group and to investigate their relations with representation theory. Let A be a Hopf algebra over a field k. A theorem of Ulbrich asserts that there is an equivalence of categories between neutral fibre functors on the category of finitedimensional A-comodules and A-Galois extensions of k. We give the c...