Mackey structures on equivariant algebraic K-theory

We study the Mackey structure of the G-spectrum K_GC associated to a monoidal G-category C. It is proved that the coefficient system of K_GC coincides, as a (graded) Mackey functor, with the system of equivariant K-groups in the sense of Fröhlich and Wall. It is also shown that for any exact category U, there exists a G-spectrum Q_GU representing the equivariant K-theory of U in the sense of Dress and Kuku, and that Q_GU is naturally G-homotopy equivalent to K_GIsoU if every short exact sequence in U splits.