January 2007 at IJCAI-07, Hyderabad, India (picture by Ali Mir Farooq)
September 2006 (picture by Rolf Hauber)
September 2006 (picture by Rolf Hauber)
March 12, 2004 (picture by Rolf Hauber)
Summer 1999, Intensivkurs Mathematik Donaueschingen, Germany (collage by
Ondrej Pindroch)