Decay of Chebyshev coefficients and error estimates of associated quadrature on shrinking intervals

Fuente: arXiv
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Autori principali: Poojara, Krishna Yamanappa, Sachan, Sabhrant, Pandey, Ambuj
Natura: Preprint
Pubblicazione: 2025
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author Poojara, Krishna Yamanappa
Sachan, Sabhrant
Pandey, Ambuj
author_facet Poojara, Krishna Yamanappa
Sachan, Sabhrant
Pandey, Ambuj
contents We analyze decay of Chebyshev coefficients and local Chebyshev approximations for functions of finite regularity on finite intervals, focusing on the framework where the interval length tends to zero while the number of approximation nodes remains fixed. For all four families of Chebyshev polynomials, we derive error estimates that quantify the dependence on the interval length for (i) the decay of Chebyshev coefficients, (ii) the approximation error between continuous and discrete Chebyshev coefficients, and (iii) the convergence of Chebyshev-based quadrature rules. These results fill a gap in the existing theory and provide a unified and rigorous description of how approximation accuracy scales on shrinking intervals, offering new theoretical insight and practical guidance for high-order numerical methods on decomposed domains. Numerical experiments corroborate the theoretical results, confirming the decay rates and illustrating the error behavior in practice.
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id arxiv_https___arxiv_org_abs_2509_14602
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Decay of Chebyshev coefficients and error estimates of associated quadrature on shrinking intervals
Poojara, Krishna Yamanappa
Sachan, Sabhrant
Pandey, Ambuj
Numerical Analysis
We analyze decay of Chebyshev coefficients and local Chebyshev approximations for functions of finite regularity on finite intervals, focusing on the framework where the interval length tends to zero while the number of approximation nodes remains fixed. For all four families of Chebyshev polynomials, we derive error estimates that quantify the dependence on the interval length for (i) the decay of Chebyshev coefficients, (ii) the approximation error between continuous and discrete Chebyshev coefficients, and (iii) the convergence of Chebyshev-based quadrature rules. These results fill a gap in the existing theory and provide a unified and rigorous description of how approximation accuracy scales on shrinking intervals, offering new theoretical insight and practical guidance for high-order numerical methods on decomposed domains. Numerical experiments corroborate the theoretical results, confirming the decay rates and illustrating the error behavior in practice.
title Decay of Chebyshev coefficients and error estimates of associated quadrature on shrinking intervals
topic Numerical Analysis
url https://arxiv.org/abs/2509.14602