The concepts of quasi-Chebyshev and weakly-Chebyshev and σ-Chebyshev were defined [3 - 7], andas a counterpart to best approximation in normed linear spaces, best coapprozimation was introduced by Franchetti and Furi...The concepts of quasi-Chebyshev and weakly-Chebyshev and σ-Chebyshev were defined [3 - 7], andas a counterpart to best approximation in normed linear spaces, best coapprozimation was introduced by Franchetti and Furi^[1]. In this research, we shall define τ-Chebyshev subspaces and τ-cochebyshev subspaces of a Banach space, in which the property τ is compact or weakly-compact, respectively. A set of necessary and sufficient theorems under which a subspace is τ-Chebyshev is defined.展开更多
As a counterpart to best approximation in normed linear spaces, the best coapproximation was introduced by Francbetti and Furl. In this paper, we shall consider the relation between coproximinality M in X and L^P（S,M...As a counterpart to best approximation in normed linear spaces, the best coapproximation was introduced by Francbetti and Furl. In this paper, we shall consider the relation between coproximinality M in X and L^P（S,M） in L^P（S,X）. Finally we give some results in cochebyshev subspaces and additional subspaces.展开更多
文摘The concepts of quasi-Chebyshev and weakly-Chebyshev and σ-Chebyshev were defined [3 - 7], andas a counterpart to best approximation in normed linear spaces, best coapprozimation was introduced by Franchetti and Furi^[1]. In this research, we shall define τ-Chebyshev subspaces and τ-cochebyshev subspaces of a Banach space, in which the property τ is compact or weakly-compact, respectively. A set of necessary and sufficient theorems under which a subspace is τ-Chebyshev is defined.
文摘As a counterpart to best approximation in normed linear spaces, the best coapproximation was introduced by Francbetti and Furl. In this paper, we shall consider the relation between coproximinality M in X and L^P（S,M） in L^P（S,X）. Finally we give some results in cochebyshev subspaces and additional subspaces.
