Variational-like inequalities for n-dimensional fuzzy-vector-valued functions and fuzzy optimization

The existing results on the variational inequality problems for fuzzy mappings and their applications were based on Zadeh's decomposition theorem and were formally characterized by the precise sets which are the fuzzy mappings' cut sets directly. That is, the existence of the fuzzy variational inequality problems in essence has not been solved. In this paper, the fuzzy variational-like inequality problems is incorporated into the framework of n-dimensional fuzzy number space by means of the new ordering of two n-dimensional fuzzy-number-valued functions we proposed [Fuzzy Sets and Systems 295 (2016) 19-36]. As a theoretical basis, the existence and the basic properties of the fuzzy variational inequality problems are discussed. Furthermore, the relationship between the variational-like inequality problems and the fuzzy optimization problems is discussed. Finally, we investigate the optimality conditions for the fuzzy multiobjective optimization problems.