“…For instance, functionals were used by Wiener for the description of Brownian motion [76], by Hohenberg and Kohn [30] to reduce the dimensionality of the Schrödinger equation in many-body quantum systems (density functional theory [46? ]), by Hopf to describe the statistical properties of turbulence [31,1,43,41], and by Bogoliubov to model systems of interacting bosons in superfluid liquid helium [8,61]. Other applications of nonlinear functionals can be found in [68,15,47,46,36,64,48,75,35,40].…”