Dubon, Eric, San Antolín Gil, Ángel
On approximation properties of matrix-valued multi-resolution analyses
Linear and Multilinear Algebra. 2023, 71(14): 2263-2281. https://doi.org/10.1080/03081087.2022.2095327
URI: http://hdl.handle.net/10045/125302
DOI: 10.1080/03081087.2022.2095327
ISSN: 0308-1087 (Print)
Abstract: 
We study approximation properties of multi-resolution analyses in the context of matrix-valued function spaces. Here, we generalize the notions of approximation order and density order given by the reference [de Boor C, DeVore RA, Ron A. Approximation from shift-invariant subspaces of L2(Rd). Trans Am Math Soc. 1994;341(2):787–806]. Indeed, we prove a characterization of the closed subspaces generated by the shifts of a single matrix-valued function that provide approximation order and/or density order α≥0. To give our conditions, we need the classical notion of approximate continuity. As a consequence, we prove necessary and sufficient conditions on a matrix-valued function to be a scaling function in a multi-resolution analysis.
Keywords:Approximate continuity, Approximation and density order, Fourier transform, Matrix-valued multi-resolution analysis, Scaling functions
Taylor & Francis
info:eu-repo/semantics/article