Variational analysis has been well recognized as an active field of mathematical (particularly nonlinear) analysis with a number of fruitful applications to other areas of mathematics, engineering, economics, and applied sciences. It is mainly based on variational principles as well as on perturbation and approximations ideas developed in broad frameworks. On one hand, this optimization-related area can be considered as an outgrowth of the classical calculus of variations, optimal control, and mathematical programming. On the other hand, it applies variational principles and techniques to a large spectrum of problems, which may not be of any variational/optimization nature.
