ISSN : 1226-0657
In this Paper, the notion of <TEX>$\varepsilon$</TEX>-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 <TEX>$\varepsilon$</TEX>>0 there exists a continuous <TEX>$\varepsilon$</TEX>-near best approximation <TEX>$\phi$</TEX> : X → M of X by M then M is a chebyshev set .