Preface. Part I: Density Matrices and Density Functionals. Are exact Kohn-Sham potentials equivalent to local functions? R.K. Nesbet, R. Colle. A theory of exact exchange relations for a single excited state; . Nagy. Correlation energy contributions from low-lying states to density functionals in the KLI approximation; C. Gutle, et al. Orbital local-scaling transformation approach to fermionic systems in the ground state; Ya.I. Delchev, et al. Reduced...