Original Article
Kyungpook Mathematical Journal 2005; 45(3): 413-421
Published online September 23, 2005
Copyright © Kyungpook Mathematical Journal.
Examples of Quadratically Hyponormal Weighted Shifts
Wei He1, Chunji Li2
1Department of Mathematics, Fudan University, Shanghai 200-433, P. R. China
2Institute of System Science, College of Sciences, Northeastern University, Shenyang, Liaoning 110-004, P. R. China
In this paper, we have a further discussion about quadratically hyponormal weighted shifts with weight sequence $alpha :1,1,sqrt{a},left( sqrt{b},% sqrt{c},sqrt{d}ight) ^{wedge }$ on the basis of sufficient conditions for positively quadratically hyponormal weighted shifts. We set examples of quadratically hyponormal weighted shifts with weight sequence of the above form, and also establish a general method for setting examples.
Keywords: quadratically hyponormal, weighted shift, weight sequence