THE K-THEORY SPECTRUM OF VARIETIES

We produce an E-infinity-ring spectrum K(Var(/kappa)) whose components model the Grothendieck ring of varieties (over a field kappa) K-0(Var(/kappa)). This is achieved by slightly modifying Waldhausen categories and the Waldhausen S-center dot-construction. As an application, we produce liftings of various motivic measures to spectrum-level maps, including maps into Waldhausen's K-theory of spaces A(*) and to K(Q).