A new type of generalized convex functions, termed preinvex functions, is further discussed in this paper. A new result that if a preinvex function satisfies intermediate-point semistrict preinvexity then it is also a semistrictly preinvex function is obtained. Furthermore, another simplified proof for a criterion of preinvex functions under weaker conditions and an impotant application of preinvex functions are given.
