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arXiv · 1801.02164

Spectrality of product domains and Fuglede's conjecture for convex polytopes

Rachel Greenfeld·Nir Lev
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Abstract

A set $Ω\subset \mathbb{R}^d$ is said to be spectral if the space $L^2(Ω)$ has an orthogonal basis of exponential functions. It is well-known that in many respects, spectral sets "behave like" sets which can tile the space by translations. This suggests a conjecture that a product set $Ω= A \times B$ is spectral if and only if the factors $A$ and $B$ are both spectral sets. We recently proved this in the case when $A$ is an interval in dimension one. The main result of the present paper is that the conjecture is true also when $A$ is a convex polygon in two dimensions. We discuss this result in connection with the conjecture that a convex polytope $Ω$ is spectral if and only if it can tile by translations.

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Rachel Greenfeld, Nir Lev. 2018-07-02. Spectrality of product domains and Fuglede's conjecture for convex polytopes. https://arxiv.org/abs/1801.02164

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