利用有限维空间的逼近性质,本文研究了由一类Fourier系数确定的乘子函数类Fq(α)(0<q≤∞)在Lp(1≤P≤∞)范数下由三角函数系给出的非线性最佳m-项逼近收敛的充分条件和必要条件。在此条件下,给出了此乘子函数类在三角函数系下最佳m-项逼近与相应的贪婪(Greedy)算法逼近的渐近估计。
The sufficient conditions and the necessary conditions for convergence of non-linear best m-term trigonometric approximation of a kind of the multiplier function classes Fq(α)(0〈q≤∞) defined by the fourier coefficients in Lp(1≤P≤∞) is studied by using the approximation properties of finite dimensional spaces. Under these conditions, the asymptotic estimations of best m-term trigonometric approximation and the corresponding greedy algorithm of the multiplier function classes are given.