Recent constrained-search advances for approximating density functionals

Abstract
For approximating the exact exchange-correlation energy functional E xc[n], it is desirable to find conditions satisfied by E xc[n]. Accordingly, it is the purpose of this paper to emphasize that the constrained-search orientation provides a working tool to help to reveal such conditions, and examples of derived coordinates-scaling conditions involving E xc[n] and v xc([n]; r) = δE xc[n]/δn(r) are given. For instance, it is shown that