Pairs of compact convex sets naturally arise in quasidifferential calculus as the sub- and superdifferentials of the directional derivative of a quasidifferentiable function (see [1]). Since the sub- and superdifferential in a given point are not uniquely determined, minimal representations are of special importance. For the 2-dimensional case, equivalent minimal pairs of compact convex sets are uniquely determined up to translations (see [2],[13]). For the 3-dimensional case, J. Grzybowski [2] gave an example of finitely many equivalent minimal pairs of compact convex sets which are not connected by translations. In this paper we construct for the 3-dimensional case a continuum of equivalent minimal pairs of compact convex sets which are not connected by translation for different indices. Moreover, we present a more general method of reducing pairs of compact convex sets by hyperplanes as in [7].

Contact details are reproduced from the original publication and may be historical.

Diethard Pallaschke

Institut für Statistik und Mathematische Wirtschaftstheorie, Universität Karlsruhe, Kaiserstr. 12, 76128 Karlsruhe, Germany.

Ryszard Urbański

Wydział Matematyki i Informatyki Uniwersytetu im Adama Mickiewicza, ul. Matejki 48/49, 60-769 Poznań, Poland

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D. Pallaschke, R. Urbański. “A Continuum of Minimal Pairs of Compact Convex Sets which are not Connected by Translations.” Journal of Convex Analysis 3 (1996), No. 1, 83–95. https://doi.org/10.68381/jca03007