Diploma in mathematics, University Frankfort/Main, Germany, 1968. Doctor of Natural Sciences, University Frankfort, Germany, 1969. Habilitation, University Tübingen, Germany, 1972.
Doctor of Philosophy (honorary), Norwegian University of Science and Technology, Trondheim, Germany, 2004.
Assistant University Tübingen, 1969-1973. Post-doctorate Carleton University, Ottawa, Canada, 1970-1971, assistant professor Canada, 1971-1972. Guest professor TH Darmstadt, Germany, 1972.
Mitarbeiter Sonderforschungsbereich Theoret. Mathematics Bonn, Germany, 1973-1974. Professor University Bonn, 1974-1978, University Bielefeld, Germany, since 1978.
Project leader Sonderforschungsbereich Diskrete Strukturen, Bielefeld, Germany, 1989-2000, chairman Germany, 1996-1999. Guest professor USTC, Heifei, China.
Member of Royal Norwegian Society Sciences and Letters.
Married Barbara Heidecker, 1974. Children: Dinah, Daniel, Clara.