Exact constants in direct and inverse approximation theorems for functions of several variables in the spaces sp

ABDULLAYEV F., Özkartepe P., Savchuk V. V., Shidlich A. L.

Filomat, vol.33, no.5, pp.1471-1484, 2019 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 33 Issue: 5
  • Publication Date: 2019
  • Doi Number: 10.2298/fil1905471a
  • Journal Name: Filomat
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1471-1484
  • Keywords: Direct theorem, Inverse theorem, K-functional, Modulus of smoothness
  • Uşak University Affiliated: No

Abstract

In the paper, exact constants in direct and inverse approximation theorems for functions of several variables are found in the spaces Sp. The equivalence between moduli of smoothness and some K-functionals is also shown in the spaces Sp.