Descripción
**Hora de inicio:** 12:00. **Hora de fin:** 13:00.
Nichols algebras of Yetter-Drinfeld modules over some Hopf algebra are important examples of braided Hopf algebras. Special cases are the plus parts of quantum enveloping algebras of semisimple Lie algebras. Nichols
algebras over groups play a fundamental role in the classification of pointed Hopf algebras. In this talk I will give an introduction to this theory. Then I will report on recent joint work with Istvan Heckenberger.
We give a new definition of the Weyl groupoid of the Nichols algebra of a semisimple Yetter-Drinfeld module. The Weyl groupoid generalizes the Weyl group of a semisimple Lie algebra. It is a crucial combinatorial invariant
to understand Nichols algebras. Our new definition is based on a very general monoidal category equivalence.