Given a nonempty set E⊂RnE \subset \R^n, we provide necessary and sufficient conditions for the existence of a convex set K⊂RnK \subset \R^n (possibly, nonclosed and unbounded) such that ext K=E\Ext K = E. Also, we describe a family of convex sets K⊂RnK \subset \R^n satisfying the equality K=conv (ext K)K = \Conv (\Ext K), and, more general, K=conv (ext K)+rec KK = \Conv (\Ext K) + \Rec K, where rec K\Rec K denotes the recession cone of KK.

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

Valeriu Soltan

Department of Mathematical Sciences, George Mason University, Fairfax, U.S.A.

vsoltan@gmu.edu
  1. G. Björck: The set of extreme points of a compact convex set, Arkiv Math. 3 (1958) 463–468.https://doi.org/10.1007/BF02589500Google Scholar
  2. C. Carathéodory: Über den Variabilitätsbereich der Fourierschen Konstanten von positiven harmonischen Funktionen, Rend. Circ. Mat. Palermo 32 (1911) 193–217.https://doi.org/10.1007/BF03014795Google Scholar
  3. B. Grünbaum: Convex Polytopes, Interscience, New York (1967).Google Scholar
  4. V. L. Klee: A note on extreme points, Amer. Math. Monthly 62 (1955) 30–32.https://doi.org/10.2307/2308014Google Scholar
  5. V. L. Klee: Extremal structure of convex sets, Arch. Math. 8 (1957) 234–240.https://doi.org/10.1007/BF01899998Google Scholar
  6. J. Lawrence, V. Soltan: On unions and intersections of nested families of cones, Beitr. Algebra Geom. 57 (2016) 655–665.https://doi.org/10.1007/s13366-016-0285-7Google Scholar
  7. J. E. Martínez-Legaz, C. Pintea: Closed convex sets of Minkowski type, J. Math. Analysis Appl. 444 (2016) 1195–1202.https://doi.org/10.1016/j.jmaa.2016.06.073Google Scholar
  8. J. E. Martínez-Legaz, M. I. Todorov: Weakly Motzkin predecomposable sets, Set-Valued Var. Analysis 25 (2017) 507–516.https://doi.org/10.1007/s11228-017-0420-0Google Scholar
  9. H. Minkowski: Gesammelte Abhandlungen. Band 2, Teubner, Leipzig (1911).Google Scholar
  10. R. Schneider: Boundary structure and curvature of convex bodies, in: Contributions to Geometry, J. Tölke, J. M. Wills (eds), Birkhäuser, Basel (1979) 13–59.https://doi.org/10.1007/978-3-0348-5765-9_1Google Scholar
  11. V. Soltan: Lectures on Convex Sets, 2nd ed., World Scientific, Hackensack (2020).https://doi.org/10.1142/11328Google Scholar
  12. T. Zamfirescu: Minkowski’s theorem for arbitrary convex sets, European J. Combin. 29 (2008) 1956–1958.https://doi.org/10.1016/j.ejc.2008.01.021Google Scholar

V. Soltan. “Extreme Points of Convex Sets.” Journal of Convex Analysis 30 (2023), No. 1, 205–216. https://doi.org/10.68381/jca30012