Journal of Complexity ( IF 1.8 ) Pub Date : 2020-11-12 , DOI: 10.1016/j.jco.2020.101537 Deimer J.J. Aleans , Sergio A. Tozoni
In this work we investigate -widths of multiplier operators and , defined for functions on the complex sphere of , associated with sequences of multipliers of the type , and , , respectively, for a bounded function defined on . If the operators and are bounded from into , , and is the closed unit ball of , we study lower and upper estimates for the -widths of Kolmogorov, linear, of Gelfand and of Bernstein, of the sets and in . As application we obtain, in particular, estimates for the Kolmogorov -width of classes of Sobolev, of finitely differentiable, infinitely differentiable and analytic functions on the complex sphere, in , which are order sharp in various important situations.
中文翻译:
估计 球面上的光滑函数集的宽度
在这项工作中,我们进行了调查 运算符的宽度 和 ,为复杂领域的函数定义 的 ,与该类型的乘法器序列相关联 , 和 , 分别用于有界函数 定义于 。如果经营者 和 受限制 进入 , , 和 是的闭合单位球 ,我们研究了 集的线性Kolmogorov宽度,Gelfand和Bernstein宽度 和 在 。作为应用,我们特别获得了Kolmogorov的估算值复球面上具有有限可微,无限可微和解析函数的Sobolev类的宽度 ,在各种重要情况下顺序都很清晰。