## IPMU Mathematics and Physics seminar

 Date: November 20, 2008, 15:30 - 17:00 Place: Seminar Room at IPMU Prefab. B, Kashiwa Campus of the University of Tokyo Speaker: Nicolai Reshetikhin (UC Berkeley & Amsterdam) Title: Quantum groups at roots of unity and invariants of links Abstract: Quantized universal enveloping algebras specialized at a primitive $\ell$-th root of unity has a large central Hopf subalgebra generated by $\ell$-th powers of Cartan subalgebra and of root elements. This talk will start with an overview of some basic facts about quantized $sl_2$ at roots of unity and its braiding properties. Then it will be used to construct invariants of links with the gauge class of generic $sl_2(C)$ flat connection in the complement. At the end the limit $\ell\to \infty$ will be discussed. Abstract.pdf