New second-order optimality conditions for directional optimality of a general set-constrained optimization problem
Wei Ouyang, Jane Ye, Binbin Zhang
TL;DR
The paper addresses second-order optimality conditions for general set-constrained problems with potentially nonconvex feasible sets, focusing on directional local optimality. It develops a framework based on directional MSCQ, directional normal cones, outer second-order tangent sets, and their asymptotic counterparts, together with the lower generalized support function. The authors obtain no-gap necessary and sufficient directional second-order conditions that do not rely on convexity, outer regularity, or nonemptiness of the second-order tangent set, thereby extending prior results. By linking M-multipliers, Clarke multipliers, and directional tangent geometry, the work provides a robust directional-optimality toolkit with potential implications for algorithm design and numerical methods in nonconvex set-constrained optimization.
Abstract
In this paper we derive new second-order optimality conditions for a very general set-constrained optimization problem where the underlying set may be nononvex. We consider local optimality in specific directions (i.e., optimal in a directional neighborhood) in pursuit of developing these new optimality conditions. First-order necessary conditions for local optimality in given directions are provided by virtue of the corresponding directional normal cones. Utilizing the classical and/or the lower generalized support function, we obtain new second-order necessary and sufficient conditions for local optimality of general nonconvex constrained optimization problem in given directions via both the corresponding asymptotic second-order tangent cone and outer second-order tangent set. Our results do not require convexity and/or nonemptyness of the outer second-order tangent set. This is an important improvement to other results in the literature since the outer second-order tangent set can be nonconvex and empty even when the set is convex.
