Riesz bases of exponentials and the Bohr topology

Carlos Cabrelli, Kathryn Hare, Ursula Molter

Published 2020-01-30Version 1

We provide a necessary and sufficient condition to ensure that a multi-tile $\Omega$ of $R^d$ of positive measure (but not necessarily bounded) admits a structured Riesz basis of exponentials for $ L^{2}(\Omega )$. New examples are given and this characterization is generalized to abstract locally compact abelian groups.