(3.7.2) Gould : Ensemble DFT 420 extends the Kohn-Sham method and related theorems to a much wider range of problems -everything including thermal states, degenerate states, "partial" electrons, excited states, and states that give direct access to fundamental gaps 423 . DFAs based on ensemble principles should be able to inherit this generality and thereby offer insights into systems that cannot be described by standard DFAs.