ON QUASI-CLASS A OPERATORS
Let QA denote the class of bounded linear Hilbert space operators T which satisfy the operator inequality
T^* |T^2| T ≥ T^* |T|^2 T.
Let f be an analytic function defined on an open neighbourhood U of σ(T) such that f is non–constant on the connected components of U. We generalize a theorem of Sheth  to f(T) ∈ QA.
- There are currently no refbacks.
ISSN: 1976-8605 (Print), 2288-1433 (Online)
Copyright(c) 2013 By The Kangwon-Kyungki Mathematical Society, Department of Mathematics, Kangwon National University Chuncheon 21341, Korea Fax: +82-33-259-5662 E-mail: firstname.lastname@example.org