• 대한수학회보
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• 제45권3호
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• pp.601-606
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• 2008

The purpose of this paper is to introduce and discuss the concept of ${\omega}$-Chebyshev subspaces in Banach spaces. The concept of quasi Chebyshev in Banach space is defined. We show that ${\omega}$-Chebyshevity of subspaces are a new class in approximation theory. In this paper, also we consider orthogonality in normed spaces.

• Journal of applied mathematics & informatics
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• 제7권2호
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• pp.585-595
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• 2000

We give various characterizations of pseudo -Chebyshev Subspaces in the spaces $L^1$(S,${\mu}$) and C(T).