Lagrangian methods for optimal control problems governed by multivalued quasi-hemivariational inequalities

The primary objective of this paper is to develop a general augmented Lagrangian approach for optimal control problems governed by multivalued quasi-hemivariational inequalities. By imposing general coercivity and monotonicity-type conditions, we establish multiple existence results for the optimal control problems. Furthermore, we establish a comprehensive characterization of the zero duality gap property for the primal-dual problems, utilizing the concept of lower semicontinuity of new perturbation functions. Our results represent a significant advancement over recent literature on the subject.