On the smoothness of positive definite and radial functions
β Scribed by Holger Wendland
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 596 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0377-0427
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β¦ Synopsis
We consider positive definite and radial functions. After giving general results concerning the smoothness of general positive definite and radial functions, we investigate the class of compactly supported, positive definite, and radial functions, where every function consists of a univariate polynomial within its support. Especially, we show that these functions necessarily possess an even number of continuous derivatives. Finally, we provide a general construction technique which we use to construct a new family of compactly supported basis functions of arbitrary smoothness.
π SIMILAR VOLUMES
Let f be a positive definite function on a locally compact abelian group G. In [3] we showed that measurability of 1 on an open neighbourhood of the zero implies measurability of f on G. As a main tool we used a result about the support of f [3, Th. I]. The aim of this note is to simplify the proof
Let G be a locally compact commutative group and let g and h be positive definite functions on G, which are not identically zero. We show that continuity of gh implies the existence of a character y of Gd (the discrete version of G) such that yg and y h are continuous. As corollary we get a special