In this thesis,we use image space analysis method to investigate the separations and optimality conditions for the optimal solution defined by the improvement set of a constrained multiobjective optimization problem.We firstly introduce two separation functions of constrained multiobjective optimization problem: a vector-valued regular weak separation function and a scalar weak separation function via a nonlinear scalarization function defined in terms of an improvement set.Secondly,saddle-point type optimality sufficient conditions for the optimal solution of the multiobjective optimization problem are established respectively by the vector-valued regular weak separation function and a scalar weak separation function.Next,we also obtain the relationships between the optimal solution and approximate efficient solution of the multiobjective optimization problem.Finally,saddle-point type optimality necessary conditions for the optimal solution of the multiobjective optimization problem are established respectively by the(regular)linear separation between the approximate image of the multiobjective optimization problem and a closed convex cone. |