Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics / Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics, (P)3059-0604; (E)3059-1309
2001, v.8 no.2, pp.153-162
Sharma, Meenu
Narang, T.D.
Sharma,,
M.
, &
Narang,,
T.
(2001). , 8(2), 153-162.
Abstract
In this Paper, the notion of $\varepsilon$-Birkhoff orthogonality introduced by Dragomir [An. Univ. Timisoara Ser. Stiint. Mat. 29(1991), no. 1, 51-58] in normed linear spaces has been extended to metric linear spaces and a decomposition theorem has been proved. Some results of Kainen, Kurkova and Vogt [J. Approx. Theory 105 (2000), no. 2, 252-262] proved on e-near best approximation in normed linear spaces have also been extended to metric linear spaces. It is shown that if (X, d) is a convex metric linear space which is pseudo strictly convex and M a boundedly compact closed subset of X such that for each $\varepsilon$>0 there exists a continuous $\varepsilon$-near best approximation $\phi$ : X → M of X by M then M is a chebyshev set .
- keywords
-
Proximinal set,
Chebyshev set,
approximatively compact set,
pseudo/strict convexity,
<tex> $\varepsilon$</tex>-Birkhoff orthogonality,
<tex> $\varepsilon$</tex>-near best approximation