Cartesian form of Putnam’s inequality for doubly commuting hyponormal \(n\)-tuples. (English) Zbl 0982.47021

Chō, M.; Curto, R. E.; Huruya, T.; Żelazko, W.

Indiana Univ. Math. J. 49, No. 4, 1437-1448 (2000).

The authors give some Cartesian form of Putnam’s inequality bounded by the area of the joint approximate point spectra for doubly commuting hyponormal \(n\)-tuples by using the inequality bounded by the area of the Xia spectra for semi-hyponormal \(n\)-tuples of operators given by Xia and give also some relation between the Taylor and Xia spectra of such \(n\)-tuples.

Reviewer: Takashi Yoshino (Sendai)

MSC:

47B20	Subnormal operators, hyponormal operators, etc.
47A13	Several-variable operator theory (spectral, Fredholm, etc.)

Keywords:

hyponornal operators; Putnam’s inequality; joint approximate point spectra; doubly commuting hyponormal \(n\)-tuples; Xia spectra; Taylor and Xia spectra