Introduction

Abstract

Founded in the 1960s the variational inequality theory is a relatively young and fast-growing field of Applied Mathematics. It is a typical example of how application problems stimulate and intensify development of both mathematical analysis and numerical treatment. During the last 30–40 years, variational inequalities have proved their importance in the mathematical modelling and numerical simulation of diverse application problems. Besides the pioneering work by Fichera in 1964 (see [FICH64]) on solution of the Signorini problem in the theory of elasticity, applications of variational inequalities in physics, mechanics, engineering, and also in mathematical programming, control and optimization problems, have been considered in many monographs, see e.g., [DULI76], [KIST80], [GLT81], [BELI82], [BENS82], [ELOC82], [BACA84], [BELI84], [CHIP84], [CRAN84], [GLOW84], [RODR87], [FRIE88], [KIOD88], [FRSP93] and [HANE96].