Continuous Fourier Transform of Vanishing Fast Functions: Explained

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Discussion Overview

The discussion centers on the properties of the continuous Fourier transform, specifically whether the Fourier transform of a continuous function that vanishes fast enough is also continuous. The scope includes theoretical aspects of Fourier analysis and properties of function spaces.

Discussion Character

  • Technical explanation

Main Points Raised

  • One participant questions if the continuous Fourier transform of a continuous and vanishing fast enough function is also continuous.
  • Another participant asserts that if a function belongs to L¹(ℝ), then its Fourier transform is uniformly continuous.
  • A participant seeks clarification on which functions are included in L¹(ℝ), leading to a definition that these are functions that are absolutely integrable, meaning their integral over the entire real line is finite.

Areas of Agreement / Disagreement

There is no consensus on the original question regarding the continuity of the Fourier transform, as it remains open for further discussion. Participants agree on the definition of L¹(ℝ) but do not resolve the initial inquiry.

Contextual Notes

The discussion does not address potential limitations or assumptions regarding the conditions under which the Fourier transform is considered, nor does it explore the implications of functions that vanish fast enough.

Delta2
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Can someone tell me if the continuous Fourier transform of a continuous (and vanishing fast enough ) function is also a continuous function?
 
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I can tell you more: in fact, if [itex]f \in L^{1}(\mathbb R)[/itex] then its Fourier Transform is uniformly continuous.
 
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Thanks very much but can u ... remind me which functions belong to L1(R)?
 
Delta² said:
Thanks very much but can u ... remind me which functions belong to L1(R)?

It are all the functions ##f:\mathbb{R}\rightarrow \mathbb{R}## which are absolutely integrable. That is, for which

[tex]\int_{-\infty}^{+\infty} |f(x)|dx[/tex]

is finite (and the integral makes sense).
 

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