The homotopy category of flat modules, and Grothendieck duality

Abstract

Let R be a ring. We prove that the homotopy category K(R-Proj) is always א1-compactly generated, and, depending on the ring R, it may or may not be compactly generated. We use this to give a description of K(R-Proj) as a quotient of K(R-Flat). The remark