English

On exposed functions in Bernstein spaces of functions of exponential type

Functional Analysis 2020-09-11 v1 Complex Variables

Abstract

For σ>0\sigma>0, the Bernstein space \ Bσ1B^1_{\sigma} consists of those L1(R)L^1(R)\ functions whose Fourier transforms are supported by [σ,σ][-\sigma,\sigma]. Since Bσ1B^1_{\sigma} is separable and dual to some Banach space, the closed unit ball D(Bσ1)D(B^1_{\sigma}) of Bσ1B^1_{\sigma}\ has sufficiently large sets of both exposed and strongly exposed points. Moreover, D(Bσ1)D(B^1_{\sigma}) coincides with the closed convex hull of its strongly exposed points. We investigate some properties of exposed points, construct several examples and obtain as corollaries the relations between the sets of exposed, strongly exposed, weak^{\ast} exposed, and weak^{\ast} strongly exposed points of D(Bσ1)D(B^1_{\sigma}).

Keywords

Cite

@article{arxiv.2009.04528,
  title  = {On exposed functions in Bernstein spaces of functions of exponential type},
  author = {Saulius Norvidas},
  journal= {arXiv preprint arXiv:2009.04528},
  year   = {2020}
}

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12 pages