"Quadratically Hyponormal Weighted Shifts with Recursive Tail" by George Exner, Il Bong Jung et al.
 

Quadratically Hyponormal Weighted Shifts with Recursive Tail

George Exner, Bucknell University
Il Bong Jung
Mi Ryeong Lee
Sun Hyun Park

Description

We characterize positive quadratic hyponormality of the weighted shift W-alpha(x) associated to the weight sequence alpha(x) : 1, 1, root x, (root u, root v, root w)(Lambda) with Stampfli recursive tail, and produce an interval in x with non-empty interior in the positive real line for quadratic hyponormality but not positive quadratic hyponormality for such a shift. (C) 2013 Elsevier Inc. All rights reserved.