Bull. Korean Math. Soc. 2010; 47(1): 179-186
Printed January 1, 2010
https://doi.org/10.4134/BKMS.2010.47.1.179
Copyright © The Korean Mathematical Society.
An-Hyun Kim and Eun-Young Kwon
Changwon National University and Changwon National University
This paper concerns the propagation phenomenon of weighted shifts. We here establish the existence of positive real numbers $b$ and $c$ $(1 < b < c )$ such that the recursive weighted shift $W_{1,(1,\sqrt{b},\sqrt{c})^\wedge}$ is quadratically but not cubically hyponormal.
Keywords: weighted shifts, subnormal, $k$-hyponormal, quadratically hyponormal, cubically hyponormal
MSC numbers: Primary 47B20, 47B37
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