Fourier transform and inversion on Schwartz functions
For a smooth rapidly decreasing f whose derivatives also decrease faster than any power, define f̂(ξ)=∫Rⁿe⁻ⁱˣ·ξf(x)dx.
Key knowledge
For a smooth rapidly decreasing f whose derivatives also decrease faster than any power, define f̂(ξ)=∫Rⁿe⁻ⁱˣ·ξf(x)dx. Then f̂ has the same property and f(x)=(2π)⁻ⁿ∫Rⁿeⁱˣ·ξf̂(ξ)dξ.
Conditions and scope
- This is the angular-frequency convention; other conventions change factors of 2π.
- The pointwise formula is stated on Schwartz space, not for arbitrary distributions or arbitrary square-integrable functions.
Sources · 1
References
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Evidence and review
Chapter 11 definition (11.1), Theorem 11.6 and Theorem 11.15 / (11.24).
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