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http://dx.doi.org/10.4134/CKMS.2013.28.4.741

ON QUASI-A(n, κ) CLASS OPERATORS  

Lee, Mi Ryeong (Department of Mathematics Kyungpook National University)
Yun, Hye Yeong (Department of Mathematics Kyungpook National University)
Publication Information
Communications of the Korean Mathematical Society / v.28, no.4, 2013 , pp. 741-750 More about this Journal
Abstract
To study the operator inequalities, the notions of class A operators and quasi-class A operators are developed up to recently. In this paper, quasi-$A(n,{\kappa})$ class operator for $n{\geq}2$ and ${\kappa}{\geq}0$ is introduced as a new notion, which generalizes the quasi-class A operator. We obtain some structural properties of these operators. Also we characterize quasi-$A(n,{\kappa})$ classes for n and ${\kappa}$ via backward extension of weighted shift operators. Finally, we give a simple example of quasi-$A(n,{\kappa})$ operators with two variables.
Keywords
class A; quasi-class A; weighted shift operator;
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