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generalized Fourier transform

(Definition)

1 Fourier-Stieltjes Transform

Definition 1.1. Given a positive definite, measurable function f(x) on the interval (−∞,∞) there exists a monotone increasing, real-valued bounded function α(t) such that:

        ∫
f (x ) =   eitxd(α(t)),
         ℝ
(1.1)

for all x ∈ ℝ except a ‘small’ set, that is a finite set which contains only a small number of values. When f(x) is defined as above and if α(t) is nondecreasing and bounded then the measurable function defined by the above integral is called the Fourier-Stieltjes transform of α(t), and it is continuous in addition to being positive definite.

References

[1]   A. Ramsay and M. E. Walter, Fourier-Stieltjes algebras of locally compact groupoids, J. Functional Anal. 148: 314-367 (1997).

[2]   A. L. T. Paterson, The Fourier algebra for locally compact groupoids., Preprint, (2001).

[3]   A. L. T. Paterson, The Fourier-Stieltjes and Fourier algebras for locally compact groupoids, (2003).


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See Also: determination of Fourier coefficients, generalized Fourier and measured groupoid transforms, 2D-FT MR- Imaging and related Nobel awards, two-dimensional Fourier transforms

Other names:  Fourier-Stieltjes transform, Stieltjes transform, Fourier-Stieltjes integral
Also defines:  Fourier-Stieltjes transform, Fourier-Stieltjes algebra of a groupoid, Fourier-Stieltjes integral
Keywords:  Fourier-Stieltjes algebra of a groupoid

Cross-references: function, measurable function

This is version 6 of generalized Fourier transform, born on 2009-01-11, modified 2009-04-19.
Object id is 373, canonical name is GeneralizedFourierTransform.
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Classification:
Physics Classification: 02. (Mathematical methods in physics)
 02.30.Nw (Fourier analysis)

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