Unbounded Hankel operators and moment problems
Functional Analysis
2019-05-16 v3 Classical Analysis and ODEs
Spectral Theory
Abstract
We find simple conditions for a non-negative Hankel quadratic form to be closable. Under some mild a priori assumption on the associated moments these sufficient conditions turn out to be also necessary. We also describe the domain of the corresponding closed form. This allows us to define unbounded non-negative Hankel operators under minimal assumptions on their matrix elements. The results obtained supplement the classical Widom condition for a Hankel operator to be bounded..
Keywords
Cite
@article{arxiv.1601.08042,
title = {Unbounded Hankel operators and moment problems},
author = {D. R. Yafaev},
journal= {arXiv preprint arXiv:1601.08042},
year = {2019}
}
Comments
An a priori condition on moments has been omitted in the previous version