Publisher : Department of Mathematics, Kyungpook National University
DOI : 10.5666/KMJ.2011.51.2.187
Title & Authors
An Algorithm for Quartically Hyponormal Weighted Shifts Baek, Seung-Hwan; Jung, Il-Bong; Moo, Gyung-Young;
Examples of a quartically hyponormal weighted shift which is not 3-hyponormal are discussed in this note. In  Exner-Jung-Park proved that if (x) : with 0 < x , then is quartically hyponormal but not 4-hyponormal. And, Curto-Lee() improved their result such as that if : with 0 < x , then is quartically hyponormal but not 3-hyponormal. In this note, we improve slightly Curto-Lee's extremal value by using an algorithm and computer software tool.