| Let C[0,+∞) be the space of continuous functions on [0, +∞). For f,g ∈C[0,+∞), their distance is defined by d(f,g)=(?)(x)(|f(x)-g(x)|)/(1+|f(x)-g(x)|), where h(x) is a strictly decreasing continuous function and h(0, 1), (?)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. |
