%0 Journal Article %T An Equivalent Condition of Preinvex Function %A ZHAO Ke-quan %J Journal of Chongqing Normal University %D 2010 %I Chongqing Normal University %X Generalized convexity has been playing an important role in mathematical programming . In this paper, an equivalent condition of twice continuously differentiable preinvex function is established by transforming multivariate real-valued function into univariate real-valued function. Suppose that X be open invex set with respect to ¦Ç,¦Çsatisfies condition C , f be twice continuously differentiable and satisfies condition D. Then f is preinvex function with respect to ¦Ç,¦Çsatisfies condition C, f be twice continuously differentible and satisfiles condition D. then f is preinvex function with respect to ¦Ç if and only if ¦Íx,y¡ÊX,¦Ç(x,y)tV2f(x)¦Ç(x,y)¡Ý0. Our results provide new thoughts to verify the preinvexity of function and also generalize some known results. %K generalized convexity %K preinvex function %K twice continuously differentiable function %K equivalent condition %U http://journal.cqnu.edu.cn/1003/pdf/0302.pdf