Optimal recovery and \(n\)-widths for convex classes of functions
The problem of optimal recovery is studied for a nonsymmetric convex class of functions. It is shown that adaptive methods may be much better than nonadaptive methods. The author defines certain Gelfand-type widths that are useful for nonsymmetric classes and proves relations to optimal error bounds for adaptive and nonadaptive methods, respectively.
scientific article; zbMATH DE number 756635