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Journal of Convex Analysis 08 (2001), No. 1, 197--222 Copyright Heldermann Verlag 2001 Variational Inequalities and Regularity Properties of Closed Sets in Hilbert Spaces Giovanni Colombo Dip. di Matematica Pura ed Applicata, Università di Padova, Via Belzoni 7, 35131 Padova, Italy Vladimirov V. Goncharov Institute of System Dynamics and Control Theory, Russian Academy of Sciences, ul. Lermontov 134, 664033 Irkutsk, Russia Some properties of closed sets which generalize concepts of Convex Analysis are compared and characterized. Some of them have a global character and are concerned with controlling the lack of monotonicity of the Frechet subdifferential of the indicator function. The connection with the local structure of sets in finite as well as in infinite dimensional spaces is also investigated. Special emphasis is given to a class of sets satisfying an external sphere condition, with locally uniform radius. Keywords: Nonsmooth analysis, Bouligand normal cones, Clarke normal cones. MSC: 49J52; 46C05 [ Fulltext-pdf (572 KB)] |