Friedhelm Waldhausen [SEP] date of birth
Friedhelm Waldhausen
Friedhelm Waldhausen (born 1938 in , Hückelhoven, Rhine Province) is a German mathematician known for his work in algebraic topology.
Academic life.
Waldhausen studied mathematics at the universities of Göttingen, Munich and Bonn. He obtained his Ph.D. in 1966 with "Eine Klasse von 3-dimensionalen Mannigfaltigkeiten" (A class of 3-dimensional manifolds) from the University of Bonn; his advisor was Friedrich Hirzebruch.
After visits to Princeton University, the University of Illinois and the University of Michigan he moved in 1968 to the
be more useful, and could be applied to other exact categories as well. Later Friedhelm Waldhausen in extended the notion of K-theory even further, to very different kinds of categories, including the category of topological spaces. 
K-theory of Waldhausen categories.
In algebra, the S-construction is a construction in algebraic K-theory that produces a model that can be used to define higher K-groups. It is due to Friedhelm Waldhausen and concerns a category with cofibrations and weak equivalences; such a