系数与值域双重约束下最佳同时逼近的特征定理的推广

１９８５年，Ｈ．Ｓｔｒａｕｓｓ在广义多项式的系数和值域同时受约束的情况下约出了最佳同时逼近的一个特征定量。本文在弱得多的条件下用不同方法证明了一个适用性更广的特征定理。     

Limit theory of restricted range approximations of complex-valued continuous functions

This paper is concerned with the problem of the best restricted range approximations of complex-valued continuous functions.Several properties for the approximating set(?)such that the classical characterization results and/or the uniqueness results of the best approximations hold are introduced.Under the very mild conditions,we prove that these properties are equivalent that(?)is a Haar subspce.     

THE CHEBYSHEV SPECTRAL METHOD WITH A RESTRAINT OPERATOR FOR BURGERS EQUATION

ＴＨＥＣＨＥＢＹＳＨＥＶＳＰＥＣＴＲＡＬＭＥＴＨＯＤＷＩＴＨＡＲＥＳＴＲＡＩＮＴＯＰＥＲＡＴＯＲＦＯＲＢＵＲＧＥＲＳＥＱＵＡＴＩＯＮ￥ＭＡＨＥＰＩＮＧ；ＧＵＯＢＥＮＹＵ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｈａｎｇｈａｉＵｎｉｖｅｒｓｉ...     

关于非线性共同逼近的强唯一性

本文首先指出文献［１］中的一个错误，举例说明弱拟凸集的最佳逼近未必具有广义强唯一性，进而讨论两类共同逼近的强唯一性，在空间是一致凸、逼近集是共同太阳集的条件下，证明了最佳共同逼近具有广义强唯一性