Simultaneous proximinality in \(L^{\infty}(\mu,X)\)

Authors

  • Eyad Abu-Sirhan Tafila Technical University, Jordan

DOI:

https://doi.org/10.33993/jnaat422-984

Keywords:

simultaneous approximation, Banach spaces
Abstract views: 279

Abstract

Let \(X\) be a Banach space and \(G\) be a closed subspace of \(X\). Let us denote by \(L^{\infty}\left( \mu,X\right) \) the Banach space of all \(X\)-valued essentially bounded functions on a \(\sigma\)-finite complete measure space \(\left( \Omega,\Sigma,\mu\right) .\) In this paper we show that if \(G\) is separable, then \(L^{\infty}\left( \mu,G\right) \) is simultaneously proximinal in \(L^{\infty}\left( \mu,X\right) \) if and only if \(G\) is simultaneously proximinal in \(X.\)

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References

A.P. Bosznoy, A remark on simultaneous approximation, J. Approx. Theory, 28 (1978), pp. 296-298. DOI: https://doi.org/10.1016/0021-9045(78)90118-1

A.S. Holland, B.N. Sahney and J.Tzimbalario, On best simultaneous approximation, J. Indian Math. Soc., 40 (1976), pp. 69-73.

C. B. Dunham, Simultaneous Chebyshev approximation of functions on an interval, Proc. Amer. Math. Soc., 18 (1967), pp. 472-477, https://doi.org/10.1090/s0002-9939-1967-0212463-6 DOI: https://doi.org/10.1090/S0002-9939-1967-0212463-6

Chong Li, On best simultaneous approximation, J. Approx. Theory, 91 (1998), pp. 332-348. DOI: https://doi.org/10.1006/jath.1996.3102

E. Abu-Sirhan, Best simultaneous approximation in Lp(I,X), Inter. J. Math. Analysis, 3 (2009) no. 24, pp. 1157-1168.

E. Abu-Sirhan and R. Khalil, Best simultaneous approximation in L∞(I,X), Indian Journal of Mathematics, 51 (2009) no.2, pp. 391-400.

Eyad Abu-Sirhan, On simultaneous approximation in function spaces, Approximation Theory XIII: San Antonio 2010, Springer Proceedings in Mathematics, NY 10013, USA 2012. DOI: https://doi.org/10.3906/mat-0904-37

Eyad Abu-Sirhan, Best p-simultaneous approximaton in Lp(μ,X), Journal of Applied Functional Analysis, 7 (2012) no. 3, pp. 225-235.

Fathi B. Saidi, Deep Hussein and R. Khalil, Best simultaneous approximation in Lp(I,E), J. Approx. Theory, 116 (2002), pp. 369-379, https://doi.org/10.1006/jath.2002.3676 DOI: https://doi.org/10.1006/jath.2002.3676

G. A. Watson, A charaterization of best simultaneous approximation, J. Approx. Theory, 75 (1998), pp. 175-182, https://doi.org/10.1006/jath.1993.1097 DOI: https://doi.org/10.1006/jath.1993.1097

J. Mach, Best simultaneous approximation of bounded functions with values in certain Banach spaces, Math. Ann., 240 (1979), pp. 157-164, https://doi.org/10.1007/bf01364630 DOI: https://doi.org/10.1007/BF01364630

J. Diestel and J.R. Uhl, Vector Measures, Math. Surveys Monographs, vol.15, Amer. Math. Soc., Providence, RI, 1977. DOI: https://doi.org/10.1090/surv/015

J.B. Diaz and H.W. McLaughlin, On simultaneous Chebyshev approximation and Chebyshev approximation with an additive weight function, J. Approx. Theory, 6 (1972), pp. 68-71, https://doi.org/10.1016/0021-9045(72)90082-2 DOI: https://doi.org/10.1016/0021-9045(72)90082-2

J.B. Diaz and H.W. McLaughlin, Simultaneous approximation of a set of bounded real functions, Math. Comp., 23 (1969), pp. 583-593, https://doi.org/10.1090/s0025-5718-1969-0248481-1 DOI: https://doi.org/10.1090/S0025-5718-1969-0248481-1

J. Mendoza, Proximinality in L^{p}(μ,X), J. Approx. Theory, 93 (1998), pp. 331-343, https://doi.org/10.1006/jath.1997.3163 DOI: https://doi.org/10.1006/jath.1997.3163

J. Mendoza and Tijani Pakhrou, Best simultaneous approximation in L¹(μ,X), J. Approx. Theory, 145 (2007), pp. 212-220. DOI: https://doi.org/10.1016/j.jat.2006.09.003

K. Kuratowiski and C. Ryll-Nardzewski, A general therem on selector, Bull. Acad. Polonaise Science, Series Math. Astr. Phys., 13 (1965), pp. 379-403.

S. Tanimoto, On best simultaneous approximation, Math. Japonica, 48 (1998) no. 2, pp. 275-279.

T. Pakhrou, Best simultaneous approximation in L^{∞}(μ,X), Math. Nachrichten, 281 (2008) no. 3, pp. 396-401, https://doi.org/10.1002/mana.200510610 DOI: https://doi.org/10.1002/mana.200510610

W.A Light, Proximinality in L^{p}(I,X), J. Approx. Theory, 19(1989), pp. 251-259, https://doi.org/10.1216/rmj-1989-19-1-251 DOI: https://doi.org/10.1216/RMJ-1989-19-1-251

W.A Light and E.W. Cheney, Approximation Theory in Tensor Product Spaces, Lecture Notes in Mathematics, 1169, Spinger-Velag, Berlin, 1985. DOI: https://doi.org/10.1007/BFb0075391

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Published

2013-08-01

How to Cite

Abu-Sirhan, E. (2013). Simultaneous proximinality in \(L^{\infty}(\mu,X)\). Rev. Anal. Numér. Théor. Approx., 42(2), 85–93. https://doi.org/10.33993/jnaat422-984

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