Abstract
In this paper some results that are known for extreme points of the unit ball in dual space are carried over to a more general case, namely to the case of the boundary of the ball (Γ ⊂B is the boundary of the unit ballB in the space dual toX if everyx ∈X achieves its maximum value onB at some point of Γ). For example, it is established that if a set is bounded inX and countably compact inσ(X, Γ), then it is weakly compact inX.
Similar content being viewed by others
References
J. Bourgain and M. Talagrand, “Compacité extrémale,”Proc. Amer. Math. Soc.,80, 68–70 (1980).
S. S. Khurana, “Point-wise compactness on extreme points,”Proc. Amer. Math. Soc.,83, No. 2, 347–348 (1981).
H. Rosenthal, “Point-wise compact subsets of the first Baire class, with some applications to Banach space theory,”Var. Publ. Ser. Math. Inst. Aarhus Univ., No. 24, 176–187 (1975).
S. Simons, “A convergence theorem with boundary,”Pacific J. Math.,40, 703–708 (1972).
E. Saab, “Extreme points, separability, and weakK-analyticity in dual Banach spaces,”J. London Math. Soc.,23, 165–170 (1981).
G. Grodefroy, “Boundaries of a convex set and interpolation sets,”Math. Ann.,277, 173–184 (1987).
M. Talagrand, “Espaces de Banach faiblementK-analitiques,”Ann. of Math.,110, No. 3, 407–438 (1979).
A. V. Arkhangel'skii,Topological Spaces of Functions [in Russian], Izd. Moskov. Univ., Moscow (1989).
J. R. Giles,Convex Analysis with Application in the Differentiation of Convex Functions, Pitman, London (1982).
J. Elton, “Extremely weakly unconditionally convergent series,”Israel J. Math.,40, No. 3, 4, 255–258 (1981).
V. P. Fonf, “Weakly extremal properties of Banach spaces,”Mat. Zametki [Math. Notes],45, No. 6, 83–91 (1989).
J. Diestel,Sequences and Series in Banach Spaces, Springer-Verlag, New York (1984).
V. P. Fonf, “Superfirst category sets in Banach spaces,”Funktsional. Anal. i Prilozhen. [Functional Anal. Appl.],25, No. 4, 66–69 (1991).
Author information
Authors and Affiliations
Additional information
Translated fromMatematickeskie Zametki, Vol. 59, No. 5, pp. 753–758, May, 1996.
Rights and permissions
About this article
Cite this article
Rybakov, V.I. On convergence on the boundary of the unit ball in dual space. Math Notes 59, 543–546 (1996). https://doi.org/10.1007/BF02308822
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02308822