Visiting ( ≥ 1 months) :

    July 2000 - Aug. 2000: McMaster University, Canada.

    Sep. 2000 - Sep. 2001: Bar-Ilan University, Israel.

    March 2002 - July 2002: NCTS in Tsinghua University, Taiwan.

    Sep. 2002 - Feb. 2003: CMA in Australia National University, Australia.

    May 2003 - June 2004: MPI of Mathematics in Science, Leipzig, Germany.

    Sep. 2008 - June 2009: Institute for Advanced Study, USA.

    July 2011: Universit`a di Firenze, Italy.

    Feb. 2012, Jan. 2013, July - Aug. 2014: Institut des Hautes Etudes Scientifiques (IHES), France.

    March 2016 - June 2016: University of Minnesota, USA.

    August 2017: University of McGill, Canada.