Journal of K-theory: K-theory and its Applications to Algebra, Geometry, and Topology

Research Article

K1 of Exact Categories by Mirror Image Sequences

Clayton Sherman

Department of Mathematics, Missouri State University, Springfield, MO 65897, USA csherman@missouristate.edu

Abstract

We establish a presentation for K 1 of any small exact category P, based on the notion of “mirror image sequence,” originally introduced by Grayson in 1979; as part of the proof, we show that every element of K 1(P) arises from a mirror image sequence. This provides an alternative to Nenashev's presentation in terms of “double short exact sequences.”

(Received July 27 2011)

Key Words

  • Algebraic K-theory;
  • K 1 ;
  • double short exact sequence;
  • mirror image sequence

Mathematics Subject Classification 2010

  • Primary 19D99