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Proceedings of the American Mathematical Society

Published by the American Mathematical Society since 1950, Proceedings of the American Mathematical Society is devoted to shorter research articles in all areas of pure and applied mathematics.

ISSN 1088-6826 (online) ISSN 0002-9939 (print)

The 2020 MCQ for Proceedings of the American Mathematical Society is 0.85.

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Strong unicity of best approximations in $L_ \infty (S,\Sigma ,\mu )$
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by Ryszard Smarzewski PDF
Proc. Amer. Math. Soc. 103 (1988), 113-116 Request permission

Abstract:

We prove that the set of functions in a Banach space ${L_\infty }(S,\sum ,\mu )$, which have a strongly unique best approximation in a finite dimensional subspace, is dense in the set of functions having a unique best approximation in the subspace.
References
  • James Angelos and Darrell Schmidt, Strong uniqueness in $L^{1}(\chi ,\,\Sigma ,\,\mu )$, Approximation theory, IV (College Station, Tex., 1983) Academic Press, New York, 1983, pp. 297–302. MR 754350
  • —, The prevalence of strong uniqueness in ${L^1}$, preprint.
  • E. W. Cheney, Introduction to approximation theory, McGraw-Hill Book Co., New York-Toronto, Ont.-London, 1966. MR 0222517
  • N. Dunford and J. T. Schwartz, Linear operators. I, Interscience, New York, 1958.
  • Günther Nürnberger and Ivan Singer, Uniqueness and strong uniqueness of best approximations by spline subspaces and other subspaces, J. Math. Anal. Appl. 90 (1982), no. 1, 171–184. MR 680871, DOI 10.1016/0022-247X(82)90051-8
  • Z. Semadeni, Banach spaces of continuous functions, PWN, Warsaw, 1971.
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Additional Information
  • © Copyright 1988 American Mathematical Society
  • Journal: Proc. Amer. Math. Soc. 103 (1988), 113-116
  • MSC: Primary 41A50; Secondary 41A52, 46E10
  • DOI: https://doi.org/10.1090/S0002-9939-1988-0938653-6
  • MathSciNet review: 938653