This view of mathematics is essential for designing learning environments and curricula, for conducting empirical studies on truly mathematical processes and also for implementing the findings of mathematics education in teacher education, where it is crucial to take systemic constraints into account.
Erich Ch. Wittmann finished his studies of mathematics and physics at the University of Erlangen from 1959 to 1964 and his practical training as a teacher for the gymnasium in 1966 with the Bavarian State Examination and the PhD in mathematics in 1967. After three years in mathematical research at the Dept. of Mathematics/Erlangen he was appointed full professor of mathematics education at the University of Dortmund. In 1987 he was co-founder of the developmental research project Mathe 2000. His international reputation has been acknowledged by the invitation to a plenary lecture at ICME 9.