Year: 2026
Type: article
Abstract: Let $$\{\varphi _{j}(x,y)\}_{j =1}^{\infty }$$ { φ j ( x , y ) } j = 1 ∞ be a uniformly bounded orthonormal system on $$[0,1]^2$$ [ 0 , 1 ] 2 , $$\{A_{n}\}_{n=1}^{\infty }$$ { A n } n = 1 ∞ be sequence of bounded subsets of $$\mathbb {Z}_{+}=\{1, 2, \dots \}$$ Z + = { 1 , 2 , ⋯ } and $$\{N_n\}$$ { N n } denote the number of elements in $$A_n$$ A n . Let also $$L_{A_n}(x,y)$$ L A n ( x , y ) and $$S_{A_{n}}(f; x,y)$$ S A n ( f ; x , y ) denote, respectively, the Lebesgue function and the partial sum of the Fourier series of a function f with respect to the system $$\{\varphi _{j}(x,y)\}$$ { φ j ( x , y ) } corresponding to the indices from $$A_n$$ A n
Author: Rostom Getsadze
Institution: KTH Royal Institute of Technology
Language: English
Subfield: Applied Mathematics
Field: Mathematics
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,990
Funder: Kungliga Tekniska Högskolan
OpenAlex ID: W7166712372