A Helson-Szegö theorem for subdiagonal subalgebras with applications to Toeplitz operators
Abstract
We formulate and establish a noncommutative version of the well known Helson–Szegö theorem about
the angle between past and future for subdiagonal subalgebras. We then proceed to use this theorem to
characterise the symbols of invertible Toeplitz operators on the noncommutative Hardy spaces associated
to subdiagonal subalgebras.
URI
http://hdl.handle.net/10394/14260https://doi.org/10.1016/j.jfa.2013.05.015
http://www.sciencedirect.com/science/article/pii/S0022123613001602