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arXiv · 2602.03952

Using wave packet decompositions to construct function spaces: a user guide

Pierre Portal
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Abstract

We survey the construction of a range of function spaces used in harmonic analysis of PDE, including classical results as well as recent developments. We frame these constructions in a common conceptual framework, where these function spaces arise as retracts of simple function spaces over phase space, through a projection associated with a wave packet decomposition. Finding appropriate function spaces to study a given PDE then consists in choosing a relevant wave packet decomposition. We provide a user guide to making such choices, and constructing the corresponding function spaces. This is done mostly by surveying recent constructions, but we also include a new construction, adapted to Schrödinger operators of the form $Δ- V$ for $V \geq 0$, as a sneak peek into upcoming joint work with Dorothee Frey, Andrew Morris, and Adam Sikora.

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Pierre Portal. 2026-09-15. Using wave packet decompositions to construct function spaces: a user guide. https://arxiv.org/abs/2602.03952

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