Advantages and Drawbacks of Variational Inequality Formulations

In recent years, the variational inequality framework has been recognized as a powerful modelling tool in operations research and economics, whenever equilibrium relationships among several agents occur. This interest has prompted researchers to develop eecient algorithms for solving variational inequalities in nite dimensional spaces. In this presentation we will try to assess the advantages and possible drawbacks of variational inequality formulations, focusing on four problems: oligopoly models, traac assignment, bilevel programming, multicriterion equilibrium. Each topic will be analyzed from the modelling and computational points of view. In particular we will try to assess whether the variational inequality formulations of these models has led to a better understanding of their inner structure and to eecient solution algorithms.