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On Gâteaux Differentiability of Convex Functions in WCG Spaces

Published online by Cambridge University Press:  20 November 2018

Jan Rychtář*
Affiliation:
Department of Mathematical Sciences, University of North Carolina at Greensboro, Greensboro, NC 27402, U.S.A. e-mail: [email protected]
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Abstract

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It is shown, using the Borwein–Preiss variational principle that for every continuous convex function $f$ on a weakly compactly generated space $X$, every ${{x}_{0}}\in X$ and every weakly compact convex symmetric set $K$ such that $\overline{\text{span}}K=X$, there is a point of Gâteaux differentiability of $f$ in ${{x}_{0}}+K$. This extends a Klee's result for separable spaces.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2005

References

[1] Borwein, J. and Preiss, D., A smooth variational principle with applications to subdifferentiability and differentiability of convex functions. Trans. Am. Math. Soc. 303(1987), 517527.Google Scholar
[2] Deville, R., Godefroy, G., and Zizler, V., Smoothness and renormings in Banach spaces. Pitman Monographs and Surveys in Pure and Applied Mathematics 64, Wiley, New York, 1993.Google Scholar
[3] Fabian, M., Gâteaux differentiability of convex functions and topology. Weak Asplund spaces. Canadian Mathematical Society Series of Monographs and Advanced Texts. John Wiley and Sons, New York, 1997 Google Scholar
[4] Fabian, M., Habala, P., Hájek, P., Santalucia, V. Montesinos, Pelant, J., and Zizler, V.. Functional analysis and infinite-dimensional geometry. CMS Books in Mathematics 8, Springer-Verlag, New York, 2001.Google Scholar
[5] Klee, V., Some new results on smoothness and rotundity in normed linear spaces. Math. Ann. 139(1959), 5163.Google Scholar
[6] Phelps, R. R., Convex functions, monotone operators and differentiability. Second edition, Lecture Notes in Mathematics 1364, Springer-Verlag, Berlin, 1993.Google Scholar