English

Fourier nonuniqueness sets for the hyperbola and the Perron-Frobenius operators

Classical Analysis and ODEs 2020-09-22 v1 Analysis of PDEs Dynamical Systems

Abstract

Let Γ\Gamma be a smooth curve or finite disjoint union of smooth curves in the plane and Λ\Lambda be any subset of the plane. Let X(Γ)\mathcal X(\Gamma) be the space of all finite complex-valued Borel measures in the plane which are supported on Γ\Gamma and are absolutely continuous with respect to the arc length measure on Γ.\Gamma. Let AC(Γ,Λ)={μX(Γ):μ^Λ=0},\mathcal{AC}(\Gamma,\Lambda)=\{\mu\in \mathcal{X}(\Gamma) : \hat\mu|_{\Lambda}=0\}, then we prove the following results: \begin{enumerate}[(a)] \item For a rational perturbation of Λβ\Lambda_\beta namely, Λβθ=((Z+{θ})×{0})({0}×βZ),\Lambda_\beta^\theta=\left((\mathbb Z+\{\theta\})\times\{0\}\right)\cup\left(\{0\}\times\beta\mathbb Z\right), where θ=1/p, for some pN,\theta=1/{p},~\text{for some}~{p}\in\mathbb N, and β\beta is a positive real, AC(Γ,Λβθ)\mathcal{AC}\left(\Gamma,\Lambda_\beta^\theta\right) is infinite-dimensional whenever β>p.\beta>p. \smallskip \item For a rational perturbation of Λγ\Lambda_\gamma namely, Λγθ=((2Z+{2θ})×{0})({0}×2γZ),\Lambda_\gamma^\theta=\left((2\mathbb Z+\{2\theta\})\times\{0\}\right)\cup\left(\{0\} \times2\gamma\mathbb Z\right), where θ=1/q, for some qN,\theta=1/q,~\text{for some}~q\in\mathbb N, and γ\gamma is a positive real, AC(Γ+,Λγθ)\mathcal{AC}\left(\Gamma_+,\Lambda_\gamma^\theta\right) is infinite-dimensional whenever γ>q.\gamma>q. \end{enumerate}

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Cite

@article{arxiv.2009.09516,
  title  = {Fourier nonuniqueness sets for the hyperbola and the Perron-Frobenius operators},
  author = {Deb Kumar Giri},
  journal= {arXiv preprint arXiv:2009.09516},
  year   = {2020}
}

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20 pages