Koch was born in
Potsdam on 5 October 1932. Koch studied from 1952 to 1957 at the
Humboldt-Universität zu Berlin. From 1957 to 1959, he worked in the semiconductor plant at
Teltow. From 1959, he was a member of the Institute for Mathematics of the
Akademie der Wissenschaften der DDR, where he received in 1964 his
promotion (Ph.D.) and in 1965 his
habilitation. He studied under
Hans Reichardt and
Igor Shafarevich (1960–61 in
Moscow). The famous "Number Theory" textbook by Shafarevich and
Borevich was translated by Koch from Russian into German. Koch was from 1969 to 1991 the head of the research group at the Institute for Mathematics and from 1992 to 1996, the head of a working group at the Humboldt University, where he became a full professor in 1992. He was on research sabbaticals in Moscow,
Saint Petersburg, and
Novosibirsk and at the
University of Paris,
University of Montreal,
University of Alberta,
University of Cambridge,
ETH Zürich, the Stefan Banach International Mathematical Center in
Warsaw, and the
Max-Planck-Institut für Mathematik in
Bonn. Koch's research dealt with, among other topics, the
Galois theory of
algebraic number fields, p-extensions of number fields, cubic number fields, and class field theory. He was a member of the Akademie der Wissenschaften der DDR. He was a full member of the
Academy of Sciences Leopoldina, the
Academia Europaea, and the
Berlin-Brandenburgische Akademie der Wissenschaften. He was a corresponding member of the
Heidelberger Akademie der Wissenschaften. In 1986 he was an Invited Speaker at the
ICM in 1986 in
Berkeley, California. In 1993 he became a member of the editorial staff of the
Mathematische Nachrichten. Koch died on 12 November 2024, at the age of 92. ==Selected publications==