ρ-Invex Functions and ( F , ρ)Convex Functions: Properties and Equivalences

-invexity, -pseudo invexity and -quasi invexity (and their extentions to nondifferentiable Lipschitz functions) have been used to weaken the assumption of convexity in solving duality problems or to state sufficient optimality conditions in nonlinear programming. An attempt to generalize further these concepts has been done with the introduction of ( F , )convexity for differentiable and nondifferentiable Lipschitz functions. Theorems and results regarding both the duality problems and the sufficience of Kuhn-Tucker conditions have been reproduced for these new classes of functions. The aim of this article is to show that for both differentiable and nondifferentiable Lipschitz functions ( F , )convexity is not a generalization of -invexity, but these families of functions coincide.