One of the first applications of the local AC to the development of DFAs was to derive the B88 correlation functional 166 Given that the global AC is the founding principle underpinning (global) hybrid functionals (see (2.4.2), (2.4.4), and (2.4.6) above), , a local AC should be relevant for local hybrid functionals (LHs) with position-dependent exact-exchange admixture. Let us mention in passing our early attempts to derive local mixing functions for LHs from local AC interpolation. Other important hyper-GGA functionals simulate strong correlation effects and also make use of local interpolations. Most notable in this context are recent efforts to include the SCE limit (λ → ∞) of the AC by local AC interpolation. Importantly, the local AC approach has advantages compared to the global AC in terms of achieving size-consistency for DFAs in the presence of degeneracies. (2.4.8) Kronik : An important concept that I have found to be very useful is that of generalized Kohn-Sham theory, introduced by This involves mapping of the manyelectron system onto a partially interacting model system, represented by a single Slater determinant, such that the ground-state electron density is conserved. The original Kohn-Sham theory then emerges as a special case of generalized Kohn-Sham theory, where the partial interaction is set to zero.