On NCP-functions

In this paper we reformulate several NCP-functions for the nonlinear comple mentarity problem (NCP) from their merit function forms and study some impo rtant properties of these NCP-functions. We point out that some of these NC P-functions have all the nice properties investigated by Chen, Chen and Kan zow [2] for a modified Fischer-Burmeister function, while some other NCP-fu nctions may lose one or several of these properties. We also provide a modi fied normal map and a smoothing technique to overcome the limitation of the se NCP-functions. A numerical comparison for the behaviour of various NCP-f unctions is provided.