P. Ebeling, F. Keune
abstract:
The K-theory of rings can be defined in terms of nonabelian derived functors 
[see the second author, "Nonabelian derived functors and algebraic K-theory", 
in: Springer-Verlag, Lecture Notes in Mathematics 341 (1973) 166--176; see also 
the books of H. Inassaridze, "Algebraic K-theory" (Mathematics and its 
Applications 311, Kluwer Publ. Group, 1995) and "Non-abelian homological algebra 
and its applications" (Mathematics and its Applications 421, Kluwer Publ. Group, 
1997) for a similar approach]. In fact both Swan's theory and Quillen's theory 
can be described this way. The equivalence of both K-theories was proved by S. 
M. Gersten ["K-theory of free rings", Commun. Algebra 1 (1974) 39--64]. In this 
paper we give a proof using these descriptions that involve nonabelian derived 
functors.