- Ph.D. Mathematics, Bielefeld, Germany 2002 (Advisor Anthony Bak)
- PostDoc. Australian National University, Canberra 2002-2003 (Host Amnon Neeman)
- Max Planck Ins. Bonn, Germany, part of 2003-2004-2005-2007
- U. California, San Diego, May-June 2005 (Host Adrian Wadsworth)
- IHES, France, July-August 2006
- U. California, San Diego, September 2006
- Korean Institute for Advance Study, Seoul, January 2007
- ICTP, Trieste, Italy, May 2008
- City University of New York, Aug 2008 to Jan 2009 (Host Raymond Hoobler)