Research visits and guest professorships

• 1988 Visitor at The Institute of Physical and Chemical Research (RIKEN) in Tokyo for 1 month, Japanese Government Research Award.
• 1991, 94, 96 Visiting Professor of Algebra (Profesor Visitante de Algebra) at the Universidad de Alcalá de Henares, Madrid, for 1 month each.
• 1993, 98 Visitor at the Academia Sinica in Beijing and the Computer Science Department of the Fudan University in Shanghai, research cooperation FWF and NSFC, for 1 month each.
• 1998 Visiting Professor at the School of Mathematics & Statistics of The University of Sydney for 1 month.
• 2001 Visiting Professor at the University of Salzburg, course on “Symbolisches Rechnen (Computeralgebra)” in the fall semester 2001/02
• 2002 Visiting Professor at the Institute of Mathematics and Informatics at the University of Debrecen for 1 week.
• 2003 Visiting Research Scientist at the Courant Institute of Mathematical Sciences, New York University for 1 month (July 2003).
• 2004 Visiting Professor at the Department of Algebra of the Charles University Prague for 1 week
• 2005 Visiting Professor at the Department of Mathematics of the University of Alcalá, Madrid for 1 month (March 2005).
• 2006 Visiting Professor at the Department of Mathematics of the Aristotle University of Thessaloniki for 1 week
• 2006 Guest Researcher at the Erwin Schrödinger Institute for Mathematical Physics (ESI), University of Vienna, Austria, 1 week (Nov. 2006)
• 2008 Visiting Researcher at the Department of Mathematics of Beihang University, Beijing for 2 weeks (March 2008)