K-Theory of the Commutator Ideal

Germain, Emmanuel

UFR de Mathématiques, Université Paris 7, 2 place Jussieu, 75251 Paris Cedex 05, e-mail: [email protected]

K-Theory 23(1):p 41-52, May 2001.

We consider for unital c^*-algebras the short exact sequence 0→ I→ A *_C B → A ⊗_max B→ 0 and give an explicit formula for the boundary map for separable C^*-algebras for which the Künneth formula for tensor products holds without Tor-terms. In the course of the article, we study the similar case of an ideal concerning one-relator groups.