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Journal of Convex Analysis 30 (2023), No. 1, 329--342 Copyright Heldermann Verlag 2023 Rotundity Properties, and Non-Extendability of Lipschitz Quasiconvex Functions Carlo Alberto De Bernardi Dip. di Matematica per le Scienze Economiche, Finanziarie ed Attuariali, Università Cattolica del Sacro Cuore, Milano, Italy carloalberto.debernardi@unicatt.it Libor Vesely Dip. di Matematica "F. Enriques", Università degli Studi di Milano, Italy libor.vesely@unimi.it Let A be an open convex subset of a real normed linear space X. We prove that if the boundary of A contains a non-LUR point then there exists a Lipschitz quasiconvex function f from A to R not admitting any continuous quasiconvex extension to the whole X. Keywords: Lipschitz function, quasiconvex function, LUR point, exposing functional. MSC: 46A55, 52A05; 52A99, 26B25. [ Fulltext-pdf (140 KB)] for subscribers only. |