A Subnormal Semigroup without Normal Extension

1 February 1978

journal article
Published by JSTOR in Proceedings of the American Mathematical Society

Vol. 68 (2) , 176-178
https://doi.org/10.2307/2041766

Abstract

Theorem 1. There exists a subnormal semigroup with no commuting normal extension. Theorem 2. There exist two commuting quasinormal operators without commuting normal extension.

Keywords

SUBNORMAL OPERATOR
QUASI-NORMAL OPERATOR
COMMUTING NORMAL EXTENSION
SUBNORMAL SEMIGROUP

This publication has 3 references indexed in Scilit:

A Hilbert space problem book (2nd edition), by P. R. Halmos. Pp 369. £43. 1982. ISBN 0-387-90685-1 (Springer)
The Mathematical Gazette, 1989
Commuting subnormal operators
Illinois Journal of Mathematics, 1978
ON THE COMMUTATIVE FAMILY OF SUBNORMAL OPERATORS
Hokkaido Mathematical Journal, 1958