caa a22 4500 605523517 CHVBK 20210128100749.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s10958-015-2549-4 doi (NATIONALLICENCE)springer-10.1007/s10958-015-2549-4 Stasyuk Sergei Institute of Mathematics of the NAS of Ukraine, 3, Tereshchenkovskaya Str., 01601, Kiev, Ukraine aut Approximations of the classes MB p , θ r of periodic functions of several variables by polynomials according to the Haar system [Elektronische Daten] [Sergei Stasyuk] Some problems of approximation of the classes MB p,θ r of periodic functions of several variables by polynomials constructed by the Haar system are investigated. For the functions of these classes, the exact-order estimates of the best m-term approximation by polynomials according to the Haar system and the upper bounds of approximations by step-hyperbolic Fourier-Haar sums are obtained. Springer Science+Business Media New York, 2015 Approximation of functions of several variables nationallicence Haar system nationallicence step-hyperbolic cross nationallicence best m -term approximation nationallicence Journal of Mathematical Sciences Springer US; http://www.springer-ny.com 210/1(2015-10-01), 76-85 1072-3374 210:1<76 2015 210 10958 https://doi.org/10.1007/s10958-015-2549-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10958-015-2549-4 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Stasyuk Sergei Institute of Mathematics of the NAS of Ukraine, 3, Tereshchenkovskaya Str., 01601, Kiev, Ukraine aut NATIONALLICENCE 773 0- Journal of Mathematical Sciences Springer US; http://www.springer-ny.com 210/1(2015-10-01), 76-85 1072-3374 210:1<76 2015 210 10958