给出了保证最佳一致逼近元唯一存在的哈尔条件的等价定义。
An equivalent characterization of Haar condition is given in this paper, which guarantees the existence and uniqueness of best uniform approximation.
本文证明了一致凸线性距离空间存在唯一的最佳联合逼近元。
In this paper, it is proved that in the uniform convexity linear metric space there exists a unique best simultaneous approximation element.
同时，作为应用，研究了最佳联合逼近元的存在性与唯一性问题。
As applications, existence and uniqueness of a best simultaneous approximation element are studied.
应用推荐