A formula for -hyponormality of backstep extensions of subnormal weighted shifts

Authors:
Il Bong Jung and Chunji Li

Journal:
Proc. Amer. Math. Soc. **129** (2001), 2343-2351

MSC (2000):
Primary 47B37

DOI:
https://doi.org/10.1090/S0002-9939-00-05844-5

Published electronically:
December 28, 2000

MathSciNet review:
1823917

Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Let be a weight sequence of positive real numbers and let be a subnormal weighted shift with a weight sequence . Consider an extended weight sequence with and let for , where is the set of natural numbers. We obtain a formula to find the interval , which provides several examples to distinguish the classes of -hyponormal operators from one another.

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Additional Information

**Il Bong Jung**

Affiliation:
Department of Mathematics, Kyungpook National University, Taegu 702–701, Korea

Email:
ibjung@kyungpook.ac.kr

**Chunji Li**

Affiliation:
Department of Mathematics, Yanbian University, Yanji 133-002, People’s Republic of China

Address at time of publication:
TGRC, Kyungpook National University, Taegu 702-701, Korea

Email:
chunjili@hanmail.com

DOI:
https://doi.org/10.1090/S0002-9939-00-05844-5

Keywords:
Subnormal weighted shifts,
$k$-hyponormal weighted shifts

Received by editor(s):
January 22, 1999

Received by editor(s) in revised form:
December 7, 1999

Published electronically:
December 28, 2000

Additional Notes:
The first author was partially supported by KOSEF grant 971-0102-006-2 and the Korea Research Foundation made in the program year of 1998, 1998-015-D00019. The second author was partially supported by TGRC-KOSEF

Communicated by:
David R. Larson

Article copyright:
© Copyright 2000
American Mathematical Society