I have been on the program committee of international conferences,
organized and chaired special sessions etc.
In the past few years I have organized the following conferences: an
international conference devoted to the 100th aniversary of the birth of
G. Cantor in 1995.
Several times the Norddeutsche Gruppentheorie Kolloquium (1988, 1991, 1994,
1999, 2003)
Students- Conference (Halle) (1997)
An Oberwolfach meeting p-Gruppen jointly with O. Kegel and Plesken
(1992)
An Oberwolfach meeting Gruppentheorie : Struktur der endlichen
einfachen Gruppen und ihre Anwendungen jointly with B. Stellmacher and
M. Liebeck (1997)
An Oberwolfach meeting Gruppen und Geometrien jointly with
M. Liebeck and B. Mühlherr (2005,2008)
Sections on DMV annual meetings
Section Algebra at the ICM Berlin 1998