English

Frames for compactly supported functions with irrational density

Functional Analysis 2025-12-05 v1

Abstract

We find sufficient conditions on a compactly supported function gg, \suppg=[a,b]\supp g = [a,b] which guarantee that the Gabor system G(g;α,β)={e2πiβmxg(xαn)}m,nZ\mathcal{G}(g;\alpha,\beta)=\{e^{2\pi i \beta m x}g(x-\alpha n)\}_{m,n\in\mathbb{Z}} is a frame for all α<ba,αβ<1,αβ\Q\alpha < b-a, \alpha\beta < 1, \alpha\beta \notin\Q. These conditions are on one hand satisfied by almost all such functions, and on the other hand are explicit enough that we can give many concrete examples of the functions gg which give us a frame e.g. g(x)=exp(1x41)χ(1,1)(x)g(x) = \exp(\frac{1}{x^4-1})\chi_{(-1,1)}(x).

Keywords

Cite

@article{arxiv.2512.04594,
  title  = {Frames for compactly supported functions with irrational density},
  author = {Yurii Belov and Aleksei Kulikov},
  journal= {arXiv preprint arXiv:2512.04594},
  year   = {2025}
}

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16 pages