The Fourier transform with Henstock--Kurzweil and continuous primitive integrals

Fuente: arXiv
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Main Author: Talvila, Erik
Format: Preprint
Published: 2025
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author Talvila, Erik
author_facet Talvila, Erik
contents For each $f\!:\!\mathbb{R}\to\mathbb{C}$ that is Henstock--Kurzweil integrable on the real line, or is a distribution in the completion of the space of Henstock--Kurzweil integrable functions in the Alexiewicz norm, it is shown that the Fourier transform is the second distributional derivative of a Hölder continuous function. The space of such Fourier transforms is isometrically isomorphic to the completion of the Henstock--Kurzweil integrable functions. There is an exchange theorem, inversion in norm and convolution results. Sufficient conditions are given for an $L^1$ function to have a Fourier transform that is of bounded variation. Pointwise inversion of the Fourier transform is proved for functions in $L^p$ spaces for $1<p<\infty$. The exchange theorem is used to evaluate an integral that does not appear in published tables.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17118
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Fourier transform with Henstock--Kurzweil and continuous primitive integrals
Talvila, Erik
Classical Analysis and ODEs
42A38, 26A39 (Primary) 46B04, 46F10 (Secondary)
For each $f\!:\!\mathbb{R}\to\mathbb{C}$ that is Henstock--Kurzweil integrable on the real line, or is a distribution in the completion of the space of Henstock--Kurzweil integrable functions in the Alexiewicz norm, it is shown that the Fourier transform is the second distributional derivative of a Hölder continuous function. The space of such Fourier transforms is isometrically isomorphic to the completion of the Henstock--Kurzweil integrable functions. There is an exchange theorem, inversion in norm and convolution results. Sufficient conditions are given for an $L^1$ function to have a Fourier transform that is of bounded variation. Pointwise inversion of the Fourier transform is proved for functions in $L^p$ spaces for $1<p<\infty$. The exchange theorem is used to evaluate an integral that does not appear in published tables.
title The Fourier transform with Henstock--Kurzweil and continuous primitive integrals
topic Classical Analysis and ODEs
42A38, 26A39 (Primary) 46B04, 46F10 (Secondary)
url https://arxiv.org/abs/2501.17118