Mathematics and Statistics Vol. 9(4), pp. 574 - 578
DOI: 10.13189/ms.2021.090416
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Quasi-Chebyshevity in

Jamila Jawdat *, Ayat Kamal
Mathematics Department, Zarqa University, Zarqa, Jordan


This paper deals with Quasi-Chebyshevity in the Bochner function spaces , where X is a Banach space. For W a nonempty closed subset of X and x ∊ X, an element w0 in W is called "best approximation" to x from W, if , for all w in W. All best approximation points of x from W form a set usually denoted by PW (x). The set W is called "proximinal" in X if PW (x) is non empty, for each x in X. Now, W is said to be "Quasi-Chebyshev" in X whenever, for each x in X, the set PW (x) is nonempty and compact in X. This subject was studied in general Banach spaces by several authors and some results had been obtained. In this work, we study Quasi-Chebyshevity in the Bochner Lp- spaces. The main result in this paper is that: given W a Quasi-Chebyshev subspace in X then Lp(μ, W) is Quasi-Chebyshev in , if and only if L1 (μ, W) is Quasi-Chebyshev in L1(μ, X). As a consequence, one gets that if W is reflexive in X such that X satisfies the sequential KK-property then Lp(μ, W) is Quasi-Chebyshev in .

Quasi-Chebyshev Set, Proximinal Set, Compact Set, Reflexive Subspace, Sequential KK-property

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Jamila Jawdat , Ayat Kamal , "Quasi-Chebyshevity in ," Mathematics and Statistics, Vol. 9, No. 4, pp. 574 - 578, 2021. DOI: 10.13189/ms.2021.090416.

(b). APA Format:
Jamila Jawdat , Ayat Kamal (2021). Quasi-Chebyshevity in . Mathematics and Statistics, 9(4), 574 - 578. DOI: 10.13189/ms.2021.090416.