Hyponormality of Toeplitz operators with generalized circulant symbols
Let \(\theta\) be a finite Blaschke product and let \(a \in H^2 \ominus (z\theta)H^2\). The paper under review contains a number of necessary and sufficient conditions, expressed in terms of the zeroes of a suitable polynomial depending on \(a\) and \(\theta\), for the hyponormality of the Toeplitz operator with generalized circulant symbol \(\varphi =\overline{za} +z \theta \overline{a}\).
scientific article; zbMATH DE number 5362151
scientific article