  We study the notion of regular ring in the sense of Vogel, which generalizes
the classical notion for non-necessarily coherent rings. We build a class of
groups "R" containing Waldhausen's class "Cl" in [Wald78] and study its
stability results. We show that for a regular ring R and a group G in "R", the
group ring R[G] is still regular. Finally, we state Vogel's excision conjecture
generalizing Waldhausen's results in [Wald78] concerning Whitehead and KNil
groups.

K-Theory and Homology;Algebraic Topology