On the Best Approximation of Certain Classes of Periodic Functions by Trigonometric Polynomials (pp. 129-144)

摘要

We obtain the estimates for the best approximation in the uniform metric of the?classes of 2π-periodic functions whose (Ψ,β)-derivatives have a given majorant ω of the modulus of continuity. It is shown that the estimates obtained here are asymptotically exact under some natural conditions on the parameters Ψ,ω and β defining the classes.