摘要
设h(x)为严格下降于零的连续函数.并且h(0)=1.设f、g∈C[0,+∞),定义距离为d(f,g)=(?)(x)|f(x)-g(x)|/1+|f(x)-g(x)|本文在这个距离空间中引进了D中间性集和弱D中间性集的概念,并且考虑了在这两类集上的最佳逼近问题,建立了最佳逼近元的一些特征刻划.
Let C[0,+∞) be the space of continuous functions on [0, +∞). For f,g 00000e C[0,+∞), their distance is defined bywhere h(x) is a strictly decreasing continuous function and h(0, I), lim h(x)=0.Here, we consider approximation by the familieэ with the D betweeness property or the weak D betweeness propert. The characterzations of best approximation are studied.
