  The arguments presented in PRL. vol. 102, 056404 (2009) are discussed in the
context of the vast literature on spectral weight transfer in doped Mott
insulators. We show that the conclusions regarding spectral weight transfer in
PRL. vol. 102, 056404 (2009) are, where novel, internally inconsistent and
where correct, have been reached at least 18 years ago.
