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Abstract

A necessary and sufficient condition is found for weak continuity of a metric projection onto a finite-dimensional subspace inl p (1<p≠2). A metric projection onto a boundedly compact set inl p is sequentially weakly upper semicontinueus. An example is given on a convex, compact set inl 2 onto which the metric projection is not weakly continuous.

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Literature cited

  1. J. M. Lambert, “The weak sequential continuity of the metric projection in Lq over separable nonatomic measure spaces,” J. Approximation Theory,11, No. 4, 350–360 (1974).

    MATH  MathSciNet  Google Scholar 

  2. V. I. Andreev, “Continuity of the metric projection in Li[S, σ, Μ]. Theory of approximation of functions,” Theses of the International Conference, Kaluga (1975), pp. 3–4.

  3. R. B. Holmes, “On the continuity of best approximation operators,” Symposium on Infinite Dimensional Topology, Baton Rouge, 1967, Princeton Univ. Press and Univ. Tokyo Press, Princeton (1972), pp. 137–157.

    Google Scholar 

  4. B. B. Panda and O. P. Kapoor, “On equidistant sets in normed linear spaces,” Bull. Austral. Math. Soc.,11, No. 3, 443–454 (1974).

    MathSciNet  Google Scholar 

  5. C. A. Kottman and Lin Bor-Luh, “The weak continuity of metric projection,” Michigan Math. J.,17, No. 4, 401–404 (1970).

    MathSciNet  Google Scholar 

  6. G. Godini, “Proprietati de semicontinuitate slaba ale proiecţiei metrice cu valori mulţimi,” Stud. Cercet. Mat.,25, No. 9, 1303–1309 (1973).

    MATH  MathSciNet  Google Scholar 

  7. V. I. Andreev, “Continuity of the metric projection in C(Q),” Metric Questions in the Theory of Functions and Mappings, No. 6, Kiev (1975), pp. 3–15.

    Google Scholar 

  8. I. Singer, Best Approximation in Normed Linear Space by Elements of a Linear Subspace, Grundlehren Math. Wiss., 171, Springer-Verlag, Berlin-New York (1970).

    Google Scholar 

  9. L. A. Lyusternik and V. I. Sobolev, Elements of Functional Analysis [in Russian], Nauka, Moscow (1965).

    Google Scholar 

  10. V. L. Klee, “Convexity of Chebyshev sets,” Math. Ann.,142, No. 3, 292–304 (1961).

    MATH  MathSciNet  Google Scholar 

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Translated from Matematicheskie Zametki, Vol. 22, No. 3, pp. 345–356, September, 1977.

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Balaganskii, V.S. Weak continuity of metric projections. Mathematical Notes of the Academy of Sciences of the USSR 22, 681–687 (1977). https://doi.org/10.1007/BF02412495

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  • DOI: https://doi.org/10.1007/BF02412495

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