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arXiv · 2212.02313

Exponential Riesz bases in $L^2$ on two interval

Yurii Belov·Mikhail Mironov
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Abstract

We give sufficient conditions for the exponential system to be a Riesz basis in $L^2(E)$, where $E$ is a union of two intervals. We show that these conditions are close to be necessary. In addition, we demonstrate ``extra point effect'' for such systems, i.e. it may happen that the Riesz basis in $L^2(E)$ differs by one point from the Riesz basis on an interval.

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Yurii Belov, Mikhail Mironov. 2022-12-02. Exponential Riesz bases in $L^2$ on two interval. https://doi.org/10.1093/imrn%2Frnad125

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