Forster received his
Diplom in 1960 from
Ludwig-Maximilians-Universität München (LMU). There he received his
doctorate in 1961. His thesis
Banachalgebren stetiger Funktionen auf kompakten Räumen (Banach algebras of continuous functions on compact spaces) was supervised by
Karl Stein. In 1965 Forster also completed his habilitation in Munich. After spending the academic year 1966–1967 at the
Institute for Advanced Study and the academic year 1967–1968 as a substitute professor at the
University of Göttingen, he became a full professor at the
University of Regensburg in 1968. In 1968–1969 he was a visiting professor at the
University of Geneva. In 1975, he moved to the
University of Münster. Since 1982 he has been a professor at the Mathematical Institute of the Ludwig-Maximilians-Universität München. Even after his retirement in summer 2005, he still regularly offers lectures for advanced students. In 1970, he was an invited speaker with talk
Topologische Methoden in der Theorie Steinscher Räume (Topological methods in the theory of
Stein spaces) at the
International Congress of Mathematicians in
Nice. In 1984 he became a member of the
Bavarian Academy of Sciences and Humanities. Forster's research deals mainly with
complex analysis, but also with questions of
algebraic geometry,
analytic number theory, and
algorithmic number theory. His program ARIBAS, an interpreter with a
Pascal-like syntax, offers powerful
arbitrary-precision arithmetic and various library functions based on such computational arithmetic. ARIBAS, available under the
GNU General Public License, also serves as the basis for the algorithms discussed in Forster's book
Algorithmische Zahlentheorie (Algorithmic number theory). He wrote two appendices for the 2nd edition of
Dale Husemöller's book
Elliptic Curves. He discovered the
Forster–Swan theorem. ==Selected publications==