Corollary to the Hohenberg-Kohn Theorem
  In this paper we construct such a set of `degenerate' Hamiltonians $\hat{H}$, which differ by an `intrinsic' constant but represent different physical systems yet possess the same ground state density. . Thus, although the proof of Hohenberg-Kohn (HK) theorem is independent of whether the constant $C$ is additive or intrinsic, its applicability is restricted to excluding the case of the latter. This constitutes the corollary to the theorem.The corollary has also been extended to the time-dependent version of the HK theorem. 
Xiao-Yin Pan and Viraht Sahni