| since July 31, 2006 | Professor emeritus |
| 1984-2002 | Director, Institute of Mathematical Economics, University of Bielefeld |
| 1978-2006 | Full Professor of Mathematical Economics, University of Bielefeld |
| 1972-1978 | Full Professor of Mathematical Economics, University of Karlsruhe |
| 1969-1970 | Visiting Assitant Professor, University of British Columbia, Vancouver, British Columbia, Canada |
| 1968-1969 | Visiting Assistant Professor, University of Minnesota, Mineapolis, Minnesota, USA |
| 1967-1968 | Amanuensis (Visiting Assistant Professor), University of Aarhus, Denmark |
| 1964-1967 | DFG (NSF) Projects at the Universities of Göttingen and Erlangen/Nürnberg |
| 1964-1967 | DFG (NSF) Projects at the Universities of Göttingen and Erlangen/Nürnberg |
| 1971 | Habilitation in Mathematics (Second Doctorate), University of Erlangen/Nürnberg |
| 1967 | PhD, University of Erlangen/Nürnberg |
| 1965 | Diploma in Mathematics (MSc), University of Göttingen |
| 1962 | Pre-Diploma in Mathematics (BSc), University of Marburg |
