Decentralized multi-objective bilevel decision making with fuzzy demands

In a bilevel decision problem, the leader at the upper level attempts to optimize his/her objective, the follower at the lower level tries to find an optimized strategy according to each of possible decisions made by the leader. A bilevel decision problem may involve fuzzy demands which appear either in the objective functions or constraints of the leader or the follower or both. Furthermore, the leader and the follower may have multiple conflict objectives that should be optimized simultaneously. This study addresses both issues to propose a fuzzy multi-objective bilevel programming model. It then develops an approximation branch-and-bound algorithm to solve fuzzy multi-objective bilevel decision problems. Finally, two case based examples further illustrate the proposed model and algorithm.