THE VECTOR-VALUED VARIATIONAL PRINCIPLE IN BANACH SPACES ORDERED BY CONES WITH NONEMPTY INTERIORS.

We prove sharpness of efficient solutions x_k to vector optimization problems resulting from Ekeland vector variational principles. We achieve this by sharpening some of the existing vector variational principles and showing that x_k remains efficient not only for perturbations in the direction k but also for other directions of perturbations. [ABSTRACT FROM AUTHOR]