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On Positive Definite Functions over a Locally Compact Group

Published online by Cambridge University Press:  20 November 2018

J. F. Price*
Affiliation:
The Australian National University, Canberray Australia
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In this note we are concerned with several questions on positive definite functions over a Hausdorff locally compact group. The main result, Theorem A, gives some necessary and sufficient conditions for to be a positive definite function when μ is a (complex Radon) measure. In particular, is a positive definite function if and only if μL2, and Theorem B then follows by giving a complete characterization of functions of the type , where fL2. Perhaps the most interesting aspect of these results is that they provide further examples of results over a non-abelian, non-compact group, which otherwise are simple consequences (with μ, a bounded measure in Theorem A) of the theorems of Plancherel and Bochner.

Unless otherwise specified, all notation and definitions will follow [1;2]. The underlying group will always be G, a Hausdorff locally compact group with identity e, and with left Haar measure dx.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1970

References

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3. Eymard, P., Valgèbre de Fourier d'un groupe localement compact, Bull. Soc. Math. France 92 (1964), 181236.Google Scholar
4. Hewitt, E. and Ross, K. A., Abstract harmonic analysis, Vol. I (Springer-Verlag, Berlin, 1963).Google Scholar