Visiting Professor IHES Bures sur Yvette France 1981-82 Visiting Professor Warwick University, England 1982 Apl. professor RWTH Aachen 1985 Visiting Professor SFB Heidelberg 1988 Visiting Professor Research […] Center Jülich 1989 Visiting Professor MPI Mathematics Bonn 1989-91 Professor at the Jülich Research Center 1991 University Professor TU Clausthal since 1992 Visiting Professor IHES, Bures sur Yvette, France […] Visiting Professor IHES Bures sur Yvette 2003 Dean of the Faculty of Mathematics and Natural Sciences 2003-2005 Visiting Professor at the Institut Henri Poincare Paris, France 2005 Visiting professor at the
