Before 1993, I worked at the Institute of Mathematics of the Siberian Branch of Soviet, and then Russian Academy of Sciences. I held research positions of Research Fellow and from 1993 – Chief Research Fellow. At the same time, I lectured at Novosibirsk State University for math students and later for physics students (in Russia, often research and teaching appointments are different). 

Since 1993, I am Professor at the University of Illinois Urbana-Champaign. 

Also, I held several visiting positions.  Among them, Guest Professor at Max Planck Institute for Mathematics in Bonn.