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arXiv · 0906.1207

Extra Invariance of Shift-Invariant Spaces on LCA Groups

Magalí Anastasio·Carlos Cabrelli·Victoria Paternostro
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Abstract

Let G be an LCA group and K a closed subgroup of G. A closed subspace of L^2(G) is called K-invariant if it is invariant under translations by elements of K. Assume now that H is a countable uniform lattice in G and M is any closed subgroup of G containing H. In this article we study necessary and sufficient conditions for an H-invariant space to be M-invariant. As a consequence of our results we prove that for each closed subgroup M of G containing the lattice H, there exists an H-invariant space S that is exactly M-invariant. That is, S is not invariant under any other subgroup M' containing M. We also obtain estimates on the support of the Fourier transform of the generators of the H-invariant space, related to its M-invariance.

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Magalí Anastasio, Carlos Cabrelli, Victoria Paternostro. 2009-06-05. Extra Invariance of Shift-Invariant Spaces on LCA Groups. https://arxiv.org/abs/0906.1207

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