English Scientific Article (Journal Article)

- SJR Scopus - Algebra and Number Theory: Q1

Identifiers

- MTMT: 31089105
- DOI: 10.7900/jot.2018may14.2193
- WoS: 000487198600002

Subjects:

The primary purpose of the present paper is to investigate when relations of the types
vertical bar AB vertical bar = vertical bar A vertical bar vertical bar B vertical
bar, vertical bar A +/- B vertical bar <= vertical bar A vertical bar + vertical bar
B vertical bar, vertical bar vertical bar A vertical bar - vertical bar B vertical
bar vertical bar <= vertical bar A +/- B vertical bar and vertical bar(ReA) over bar
vertical bar <= vertical bar A vertical bar (among others) hold in an unbounded operator
setting. As consequences, we obtain a characterization of (unbounded) self-adjointness
as well as a characterization of invertibility for the class of unbounded normal operators.
Some examples accompany our results.

2020-09-19 03:55