  Transfer maps and projection formulas are undoubtedly one of the key tools in
the development and computation of (co)homology theories. In this note we
develop an unified treatment of transfer maps and projection formulas in the
non-commutative setting of dg categories. As an application, we obtain transfer
maps and projection formulas in algebraic K-theory, cyclic homology,
topological cyclic homology, and other scheme invariants.
