Constructive approximation of convergent sequences by eigenvalue sequences of radial Toeplitz--Fock operators

Fuente: arXiv
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Main Authors: García, Kevin Esmeral, Maximenko, Egor A.
Format: Preprint
Published: 2025
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author García, Kevin Esmeral
Maximenko, Egor A.
author_facet García, Kevin Esmeral
Maximenko, Egor A.
contents It is well known that for every measurable function $a$, essentially bounded on the positive halfline, the corresponding radial Toeplitz operator $T_a$, acting in the Segal--Bargmann--Fock space, is diagonal with respect to the canonical orthonormal basis consisting of normalized monomials. We denote by $γ_a$ the corresponding eigenvalues sequence. Given an arbitrary convergent sequence, we uniformly approximate it by sequences of the form $γ_a$ with any desired precision. We give a simple recipe for constructing $a$ in terms of Laguerre polynomials. Previously, we proved this approximation result with nonconstructive tools (Esmeral and Maximenko, ``Radial Toeplitz operators on the Fock space and square-root-slowly oscillating sequences'', Complex Anal. Oper. Theory 10, 2016). In the present paper, we also include some properties of the sequences $γ_a$ and some properties of bounded sequences, uniformly continuous with respect to the sqrt-distance on natural numbers.
format Preprint
id arxiv_https___arxiv_org_abs_2503_23276
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Constructive approximation of convergent sequences by eigenvalue sequences of radial Toeplitz--Fock operators
García, Kevin Esmeral
Maximenko, Egor A.
Functional Analysis
Operator Algebras
47B35, 30H20, 41A10, 30E05
It is well known that for every measurable function $a$, essentially bounded on the positive halfline, the corresponding radial Toeplitz operator $T_a$, acting in the Segal--Bargmann--Fock space, is diagonal with respect to the canonical orthonormal basis consisting of normalized monomials. We denote by $γ_a$ the corresponding eigenvalues sequence. Given an arbitrary convergent sequence, we uniformly approximate it by sequences of the form $γ_a$ with any desired precision. We give a simple recipe for constructing $a$ in terms of Laguerre polynomials. Previously, we proved this approximation result with nonconstructive tools (Esmeral and Maximenko, ``Radial Toeplitz operators on the Fock space and square-root-slowly oscillating sequences'', Complex Anal. Oper. Theory 10, 2016). In the present paper, we also include some properties of the sequences $γ_a$ and some properties of bounded sequences, uniformly continuous with respect to the sqrt-distance on natural numbers.
title Constructive approximation of convergent sequences by eigenvalue sequences of radial Toeplitz--Fock operators
topic Functional Analysis
Operator Algebras
47B35, 30H20, 41A10, 30E05
url https://arxiv.org/abs/2503.23276