Approximation by Spherical Functions
✍ Scribed by Hermann König
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 548 KB
- Volume
- 162
- Category
- Article
- ISSN
- 0025-584X
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✦ Synopsis
Abstract
Results on the degree of approximation of continuous or Lipschitz‐continuous functions f:S^n−1^ → ℝ on the sphere in ℝ^n^ by spherical functions of degree k are given in terms of k and n, strengthening results of Newman and Shapiro. An example of (restriction of) a norm shows the result to be the best possible in k and n. Further, results for smoother functions are discussed.
📜 SIMILAR VOLUMES
For T a topological space and X a real normed space, Y=C(T, X) denotes the space of continuous and bounded functions from T into X endowed with the sup norm. We calculate a formula for the distance :( f ) from f in Y to the set Y &1 of functions in Y which have no zeros. Namely, we prove that :( f )
## Abstract By a general argument, it is shown that Herglotz wave functions are dense (with respect to the C^∞^(Ω)‐topology) in the space of all solutions to the reduced wave equation in Ω. This is used to provide corresponding approximation results in global spaces (eg. in L2‐Sobolev‐spaces __H__^