Chebyshev centers in hyperplanes of c 0

Libor Veselý

Czechoslovak Mathematical Journal (2002)

  • Volume: 52, Issue: 4, page 721-729
  • ISSN: 0011-4642

Abstract

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We give a full characterization of the closed one-codimensional subspaces of c 0 , in which every bounded set has a Chebyshev center. It turns out that one can consider equivalently only finite sets (even only three-point sets) in our case, but not in general. Such hyperplanes are exactly those which are either proximinal or norm-one complemented.

How to cite

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Veselý, Libor. "Chebyshev centers in hyperplanes of $c_0$." Czechoslovak Mathematical Journal 52.4 (2002): 721-729. <http://eudml.org/doc/30738>.

@article{Veselý2002,
abstract = {We give a full characterization of the closed one-codimensional subspaces of $c_0$, in which every bounded set has a Chebyshev center. It turns out that one can consider equivalently only finite sets (even only three-point sets) in our case, but not in general. Such hyperplanes are exactly those which are either proximinal or norm-one complemented.},
author = {Veselý, Libor},
journal = {Czechoslovak Mathematical Journal},
keywords = {Chebyshev centers; proximinal hyperplanes; space $c_0$; Chebyshev centers; proximinal hyperplanes; space },
language = {eng},
number = {4},
pages = {721-729},
publisher = {Institute of Mathematics, Academy of Sciences of the Czech Republic},
title = {Chebyshev centers in hyperplanes of $c_0$},
url = {http://eudml.org/doc/30738},
volume = {52},
year = {2002},
}

TY - JOUR
AU - Veselý, Libor
TI - Chebyshev centers in hyperplanes of $c_0$
JO - Czechoslovak Mathematical Journal
PY - 2002
PB - Institute of Mathematics, Academy of Sciences of the Czech Republic
VL - 52
IS - 4
SP - 721
EP - 729
AB - We give a full characterization of the closed one-codimensional subspaces of $c_0$, in which every bounded set has a Chebyshev center. It turns out that one can consider equivalently only finite sets (even only three-point sets) in our case, but not in general. Such hyperplanes are exactly those which are either proximinal or norm-one complemented.
LA - eng
KW - Chebyshev centers; proximinal hyperplanes; space $c_0$; Chebyshev centers; proximinal hyperplanes; space
UR - http://eudml.org/doc/30738
ER -

References

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  2. 10.1016/0021-9045(84)90011-X, J.  Approx. Theory 40 (1984), 364–374. (1984) MR0740649DOI10.1016/0021-9045(84)90011-X
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  4. 10.1007/BF02417105, Ann. Mat. Pura. Appl.  101 (1974), 215–227. (1974) MR0358179DOI10.1007/BF02417105
  5. The best possible net and the best possible cross section of a set in a normed space, Izv. Akad. Nauk. SSSR 26 (1962), 87–106. (Russian) (1962) Zbl0158.13602MR0136969
  6. A Course in Optimization and Best Approximation. Lecture Notes in Math. 257, Springer-Verlag, 1972. (1972) MR0420367
  7. Generalized centers of finite sets in Banach spaces, Acta Math. Univ. Comenian. 66 (1997), 83–115. (1997) MR1474552
  8. A Banach space in which all compact sets, but not all bounded sets, admit Chebyshev centers, Arch. Math (to appear). (to appear) MR1967268
  9. The Chebyshev center in hyperspaces of continuous functions, Funktsional’nyj Analiz, vol. 12, A. V. Štraus (ed.), Ul’janovsk. Gos. Ped. Inst., Ul’janovsk, 1979, pp. 56–68. (Russian) (1979) MR0558342

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