Abstract
A concept of a 2-Chebyshev set in a Banach space is introduced. It is proved that a set in Hilbert space is 2-Chebyshev if and only if it is convex and closed.
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References
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Original Russian Text © P.A. Borodin, 2008, published in Vestnik Moskovskogo Universiteta, Matematika. Mekhanika, 2008, Vol. 63, No. 3, pp. 16–19.
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Borodin, P.A. Convexity of 2-Chebyshev sets in Hilbert space. Moscow Univ. Math. Bull. 63, 96–98 (2008). https://doi.org/10.3103/S0027132208030030
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DOI: https://doi.org/10.3103/S0027132208030030