Invited Academic activities

• October 1978: Visiting Professor, University of Copenhaguen.
• November 1978: Visiting Professor, University of Lund.
• December 1979: Visiting Professor Oberwolfach, R.F.A.
• April 1980: Visiting Professor, University of Dresden, Jena and Academy of Sciences, Berlin, R.D.A.
• April 1981: Visiting Professor Dresden University.
• August 1982: Visiting Professor, University of São Paulo.
• May 1983: Visiting Professor, University of São Paulo.
• May-June 1984: Visiting Professor in "Instituto de Matemática Pura y Aplicada (IMPA)" Rio de Janeiro, Brasil.
• July 1985: Visiting Professor "Instituto Venezolano de Investigaciones Científicas (IVIC)" and "Universidad Simón Bolívar", Caracas, Venezuela.
• November 1985: Visiting Professor, Instituto de Matemática Pura y Aplicada (IMPA) , Rio de Janeiro and University of São Paulo.
• September 1986: Visiting Professor, URSS Academy of Sciences.
• October 1986: Visiting Professor, Universities of Pisa and Rome "la Sapienza".
• November 1986: Visiting Professor Université de Paris XI.
• July 1987: Visiting Professor, IMPA,Rio de Janeiro.
• September 1987:Visiting Professor Université de Paris XI.
• October 1987: Visiting Professor, Academy of Sciences, URSS, Steklov Institute.
• June 1988: Visiting Professor, Universities of Rome 1 and Messina.
• June 1989: Visiting Professor Academy of Sciences, URSS, Steklov Institute.
• January 1991: Visiting Professor Academy of Sciences, URSS, Steklov Institute.
• January 1992: Visiting Professor, University of Mexico (UNAM) and CINVESTAV.
• May 1992: Visiting Professor, Centro Volterra, U. of Rome 2.
• June 1992: Visiting Professor Academy of Sciences, Russia, Steklov Institute.
• February 1993: Visiting Professor Australian National University at Canberra.
• February 1994: Visiting Professor Australian National University at Canberra.
• November 1994: Visiting Professor Louisiana State University.
• January 1996: Visiting Professor University of Genova, Italy.
• September 1996: Visiting Fellow, INRIA, Sophia-Antipolis.
• June 1998: Visiting Fellow, Institut Fourier, Université de Grenoble.
• January-February 1999: Visiting Professor, Université de Franche-Comté, Besançon, France.
• May 1999: Visiting Professor, Universidade de Lisboa, Portugal.
• July 2000:Visiting Fellow, Université de Toulouse, IRMSAC, research group of Jean Bellissard.
• May 2001: Visiting Fellow, Université de Toulouse, IRMSAC, research group of Jean Bellissard.
• January 2002: Visiting Fellow, Max Planck Institut, Dresden, Germany.
• May 2002: Visiting Fellow, Universidade de Lisboa, Portugal.
• January 2003-July 2003: Visiting Professor at the University of Reims, UFMR Mathématiques, France.
• January 2004: Visiting Professor, Institut Fourier, Grenoble, France.