Semigroup Forum

, Volume 56, Issue 2, pp 197–204 | Cite as

On Similarity to Contraction Semigroups in Hilbert Space

  • Quôc-Phóng Vu
  • Fuyuan Yao


-semigroup in Hilbert space, then T(t) is similar to a contraction semigroup. Analogously, if T is a power-bounded quasi-compact operator, then T is similar to a contraction. This latter fact is a simultaneous generalization of well known results of Sz.-Nagy and Rota. Some characterizations of bounded quasi-compact semigroups and power-bounded quasi-compact operators are also given.


Hilbert Space Contraction Semigroup Simultaneous Generalization 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© 1998 Springer-Verlag New York Inc.

Authors and Affiliations

  • Quôc-Phóng Vu
  • Fuyuan Yao

There are no affiliations available

Personalised recommendations