(2.1.25) Ayers : Arguably, any electronic structure theory method can be reformulated as a DFA by substituting its associated energy functional into the Legendre transform or its associated wave-function ansatz into the constrained search. So Hartree-Fock may be legitimately considered a DFT (a generalized Kohn-Sham DFT). Is Hartree-Fock theory and its analysis therefore DFT? Clearly, many coupled-cluster and propagator methods are also frequently analysed as DFT. I would not like to define DFT as "the sort of stuff that is done by density-functional theorists" but some work that is marketed as DFT (cf. contribution (2.1.20)) is not presented in the context of the mathematical framework of DFT (cf. contribution (2.1.1)).