In this paper we prove a concentration theorem for arithmetic K0-theory, this theorem can be viewed as an analog of R. Thomason's result (cf. ) in the arithmetic case. We will use this arithmetic concentration theorem to prove a relative fixed point formula of Lefschetz type in the context of Arakelov geometry. Such a formula was conjectured of a slightly stronger form by K. Köhler and D. Roessler in  and they also gave a correct route of its proof there. Nevertheless our new proof is much simpler since it looks more natural and it doesn't involve too many complicated computations.
© by Walter de Gruyter Berlin Boston