IMJ-PRG, France, Paris, Visiting Research Fellow, September 2018, September 2019, May-August 2021, April-May 2022.

IMPA, Brazil, Rio de Janeiro, Visiting Research Fellow, May-July 2015, July 2019

University of Vienna, Visiting Research Fellow, March-July 2009

Massachusetts Institute of Technology, Visiting Research Fellow, Jan.-Feb. 2009

Steklov Mathematics Institute, Russian Academy of Sciences, Moscow, Visiting Research Fellow, December 2008