English

Fourier transforms of bounded functions

Classical Analysis and ODEs 2026-01-26 v1

Abstract

The Fourier transform of a bounded measurable function, ff, on the real line is shown to be the second distributional derivative of a H\"older continuous function. The Fourier transform is written as the difference of 11eistf(t)dt\int_{-1}^1 e^{-ist}f(t)\,dt and the second distributional derivative of the integral t>1eistf(t)dt/t2\int_{\lvert{t}\rvert>1}e^{-ist}f(t)\,dt/t^2. The space of such Fourier transforms is isometrically isomorphic to L(R)L^\infty(\mathbb{R}). There is an exchange theorem, inversion and convolution results. The Fourier transform of the functions xcosm(a/x)x\mapsto\cos^m(a/x) for each natural number mm are computed. Also for xxsin(a/x)x\mapsto x\sin(a/x) and xarctan(x/a)x\mapsto\arctan(x/a).

Keywords

Cite

@article{arxiv.2601.16912,
  title  = {Fourier transforms of bounded functions},
  author = {Erik Talvila},
  journal= {arXiv preprint arXiv:2601.16912},
  year   = {2026}
}
R2 v1 2026-07-01T09:17:38.552Z