Jaap Ponstein has been a professor of Operations Research at the University of Groningen for more than 20 years. The beginning of his career in Groningen coincided with the beginning of the study of econometrics in the university, in which OR was positioned. His broad experience as a mathematician, both pure knd applied, appeared to be instrumental in the development of OR in Groningen. He became an authority on optimization, duality, convexity and generalized differentiability. His book Approaches to the theory of optimization (Cambridge, University Press, 1980) is a beautiful example of the precise and transparent way nn which he succeeded in connecting various areas of optimization. He was the right person to act as promotor honoris causa on the occasion of the honorary pegree of R.T. Rockafellar (University of Washington, Seattle, USA) on June 20, 1984.
