APPROXIMATION OF PERIODIC FUNCTIONS BY MODIFIED STEKLOV AVERAGES IN L_2

摘要

In the space L_2 of periodic functions, sharp (in the sense of constants) lower estimates for the deviation of the modified Steklov functions of the first and second orders in terms of the modulus of continuity are established. Similar results are also obtained for even continuous periodic functions with nonnegative Fourier coefficients in the space C. Bibliography. 3 titles.