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JOURNALS // Algebra i Analiz // Archive

Algebra i Analiz, 2024 Volume 36, Issue 5, Pages 163–172 (Mi aa1942)

Research Papers

Polynomial approximation in the mean on segments

N. A. Shirokov

St. Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences

Abstract: Let $S_k$, $1\le k\le m$ – pairs of disjoint segments, $S_k = [a_k, b_k]$, $1<p_k<\infty$ functions $f_k$ are defined on $S_k$, $f_k$ belongs to $C(S_k)$ and $f'_k$ belongs to $L^{P_k}(S_k)$. The work proves that for $n=1,2,\dots$ there are polynomials $P_n$, $ \deg P_n \le n$ that approximate all functions $f_k$ in the metric $L^{P_k}$ with weights tending to infinity when approaching points $a_k$, $b_k$.

Keywords: polynomials, approximation in the mean, $L^p$ spaces.

Received: 22.04.2024



© Steklov Math. Inst. of RAS, 2025