Set-Valued Analysis 8: 31–50, 2000. 31 © 2000 Kluwer Academic Publishers. Printed in the Netherlands. On Quantitative Stability in Optimization and Optimal Control ? A. L. DONTCHEV1,W.W.HAGER2, K. MALANOWSKI3 andV.M.VELIOV4 1 Mathematical Reviews, Ann Arbor, MI 48107, U.S.A. e-mail:
[email protected]. 2 Department of Mathematics, University of Florida, Gainesville, FL 32611, U.S.A. e-mail:
[email protected]fl.edu, http://www.math.ufl.edu/Qhager. 3 Systems Research Institute, Polish Academy of Sciences, ul. Newelska 6, 01-447 Warsaw, Poland. e-mail:
[email protected]. 4 Institute of Mathematics and Informatics, Bulgarian Acad. of Sc., 1113 Sofia, Bulgaria and Vienna University of Technology, Wiedner Hauptstr. 8-10/115, A-1040 Vienna, Austria. e-mail:
[email protected]. (Received: July 1999) Abstract. We study two continuity concepts for set-valued maps that play central roles in quan- titative stability analysis of optimization problems: Aubin continuity and Lipschitzian localization. We show that various inverse function theorems involving these concepts can be deduced from a single general result on existence of solutions to an inclusion in metric spaces. As applications, we analyze the stability with respect to canonical perturbations of a mathematical program in a Hilbert space and an optimal control problem with inequality control constraints. For stationary points of these problems, Aubin continuity and Lipschitzian localization coincide; moreover, both properties are equivalent to surjectivity of the map of the gradients of the active constraints combined with a strong second-order sufficient optimality condition. Mathematics Subject Classifications (2000): 47H04, 90C31, 49K40.