Comment on Kinetic energy in density-functional theory

In a recent paper, R. K. Nesbet [Phys. Rev. A 58, R12 (1998)] has compared the single-particle kinetic energy from the Kohn-Sham reference state theory with that of the Thomas-Fermi-like form of the, density-functional theory. We argue that, contrary to his opinion, both theories should give the same results, for N-electron ground-state density, We show also that there is no inconsistency between the kinetic-energy forms of the two theories, and no need to extend the definition of functional derivatives.