The problem of differential calculus on quantum groups

The bicovariant differential calculi on quantum groups of Woronowicz have the drawback that their dimensions do not agree with that of the corresponding classical calculus. In this paper we discuss the first-order differential calculus which arises from a simple quantum Lie algebra l _h (g) This calculus has the correct dimension and is shown to be bicovariant and complete. But it doesnot satisfy the Leibniz rule. Forsl _n this approach leads to a differential calculus which satisfies a simple generalization of the Leibniz rule.Presented at the 5th International Colloquium on Quantum Groups: Quantum Groups and Integrable Systems, Prague, 20–22 June 1996.