Approximation of Functions by $n$-Separate Wavelets in the Spaces ${L}^p(\mathbb{R})$, $1\leq p\leq\infty$
E. A. Pleshchevaab a Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg
b Ural Federal University named after the First President of Russia B. N. Yeltsin, Ekaterinburg
Abstract:
We consider the orthonormal bases of
$n$-separate MRAs and wavelets constructed by the author earlier. The classical wavelet basis of the space
$L^2(\mathbb{R})$ is formed by shifts and compressions of a single function
$\psi$. In contrast to the classical case, we consider a basis of
$L^2(\mathbb{R})$ formed by shifts and compressions of
$n$ functions
$\psi^s$,
$s=1,\ldots,n$. The constructed
$n$-separate wavelets form an orthonormal basis of
$L^2(\mathbb{R})$. In this case, the series $\sum_{s=1}^{n}\sum_{j\in\mathbb{Z}}\sum_{k\in\mathbb{Z}}\langle f,\psi^s_{nj+s} \rangle \psi^s_{nj+s}$ converges to the function
$f$ in the space
$L^2(\mathbb{R})$. We write additional constraints on the functions
$\varphi^s$ and
$\psi^s$,
$s=1,\ldots,n$, that provide the convergence of the series to the function
$f$ in the spaces
$L^p(\mathbb{R})$,
$1 \leq p \leq \infty$, in the norm and almost everywhere.
Keywords:
wavelet, scaling function, basis, multiresolution analysis.
UDC:
517.5
MSC: 42C40 Received: 19.03.2019
DOI:
10.21538/0134-4889-2019-25-2-167-176