We prove a claim by Williams that the coassembly map is a homotopy limit map.
As an application, we show that the homotopy limit map for the coarse version
of equivariant A-theory agrees with the coassembly map for bivariant
A-theory that appears in the statement of the topological Riemann-Roch
theorem.Comment: Accepted version. Several improvements from the referee, including a
more elegant proof of Lemma 3.