Delivered 100 invited talks in 40 different universities/insititutes in India and Abroad.
Reviewer for Mathematical Reviews, New York, USA. Reviewed 43 research papers.
Reviewer for Zentralblatt fur Mathematik, Germany. Reviewed 11 research papers.
Fellow of International Society of Analysis, New York, USA.
Sectional President, Indian Science Congress, 2014-15
Member of American Mathematical Society, USA.
Member of Ramanujan Mathematical Society.
Council Member of Indian Mathematical Society.
Member of Indian Science Congress.
Participated in several International and National conferences and symposia
Referee for several national and international journals.
Ph.D. examiner for several Universities and Institutes
University of Paderborn, Germany, 1981-1983.
University of Tubingen, Germany, 1981.
Technical University of Munich, Germany, 1981
University of Wurzburg, Germany, 1982.
University of Salzburg, Austria, 1982.
University of Nancy, France, 1987.
University of Strasbourg, France, 1987-1988.
Oberwalfach Insititute, Germany, 1988.
University of Paderborn, Germany, 1988-1989.
Universitat Berlin, Germany, 1991-1992.
University of Paderborn, Germany, 1992.
International Centre of Theoretical Physics, Trieste, Italy, 1993.
University of Edinburgh, U.K, 1995-1996.
University of Sheffield, England, 1996.
University of Glasgow, U.K, 1996.
University of Paderborn, Germany, 1999.
University of Edinburgh, U.K.1999-2000.
University of Yorkshire, England, 1999.
University of Belfast, Ireland, U.K. 1999.
Freie Universitat, Berlin, Germany, 2003
Freie Universitat, Berlin, Germany, 2004
University of Kabul, Afghanistan, 2006 University of Delhi Delegation
Freie Universitat, Berlin, Germany, 2008
University of Tokyo, Japan, 2012
Gunma University, Japan, 2012
Chiba University, Japan, 2012