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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2023 Volume 527, Pages 71–83 (Mi znsl7390)

Paltanea type theorems on estimation by positive discrete functionals

L. N. Ikhsanov

Saint Petersburg State University

Abstract: The article is concerned with inequalities of the type
\begin{equation*} |F(f)-F(e_0)f(x)| \le F(e_0)\omega_2(f, h), \end{equation*}
there $F$ is a functional of the form $F(f)=\sum\limits_{y \in Y}\gamma(y)f(y)$, and $Y$ is an at most countable set with no accumulation points on $\mathbb{R}$, $\gamma : Y \to (0, \infty)$.

Key words and phrases: positive operators, second modulus of continuity.

UDC: 517.51

Received: 02.11.2022



© Steklov Math. Inst. of RAS, 2024