Kolmogorov and linear widths of the weighted Besov classes with   singularity at the origin
  In this paper we obtain asymptotic estimates of Kolmogorov and linear widths of the weighted Besov classes with singularity at the origin. In addition, estimates of Kolmogorov and linear widths of finite-dimensional balls in a mixed norm are obtained. 
A.A. Vasil'eva
math.FA