1 Pinkus A. N-widths in approximation theory. New York, 1985
2 Romaniuk A S. Approximation for Besov-type classes of periodic functions in Lq space. Ukrain Mat Zh,
1991, 43(10):1398-1408
3 Romaniuk A S. Optimal trigonometric approximation and Kolmogorov widths for Besov classes of multi-
variate functions. Ukr Mat Zh, 1993, 45(5): 663-675
4 Romaniuk A S. Kolmogorov widths for classes Br
p, of multivariate periodic functions with small smooth-
ness in the space Lq. Ukr Mat Zh, 1994, 46(7): 915-926
5 Pustovoitov N N. Representation and approximation of multivariate periodic functions with a given mod-
ulus of smoothness. Analysis Math, 1994, 20: 35-48
6 Sun Yongsheng, Wang Heping. Cambridge: Representation and approximation of multivariate functions
with bounded mixed moduli of smoothness. Proceedings of the Steklov Institute of Mathematics, 1997,
219: 350-371
7 Nikol’skii S M. Approximation of Functions of Several Variables and Imbedding Theorems. New York:
Spring-Verlag, 1975
8 Zygmund A. Trigonometric Series II. Cambridge Univ Press, 1959 |