Toeplitz versus Hankel: semibounded operators
arXiv:1711.02614
Abstract
Our goal is to compare various results for Toeplitz and Hankel operators. We consider semibounded operators and find necessary and sufficient conditions for their quadratic forms to be closable. This property allows one to define and as self-adjoint operators under minimal assumptions on their matrix elements. We also describe domains of the closed Toeplitz and Hankel quadratic forms.