Complex systems fascinate because of the way dynamic microscopic interactions give rise to striking, often unexpected macroscopic structures: convection cells in fluids, patterns in ecosystems, ...

Variational principles play a fundamental role in deriving the evolution equations of physics. They work well in the case of non-dissipative evolution, but for dissipative systems, the variational ...

In this paper we consider certain nonlinear and constrained variational problems that occur in the theory of search. The problems are definitely of a nonclassical variety, but, by using a device of R.