Characterizations of weakly sharp solutions for a variational inequality with a pseudomonotone mapping

For a variational inequality problem with a pseudomonotone mapping F, we characterize the weak sharpness of its solution set C* without using gap functions. When the mapping F is also constant on C*, the characterizations of weak sharpness of C* become more succinct. As an example, a pseudomonotone+ mapping on C* is shown to be constant on C*. Consequently the weak sharpness of C* can further be described by a Gâteaux differentiable function which itself characterizes the pseudomonotonicity+ of F on C*. It turns out that several existing relevant results with differentiable gap functions can be obtained from ours.