Open AccessSpectral inclusion by the quadratic numerical range of 2 x 2 operator matrices with unbounded entries
Author(s) -
Jie Liu,
Junjie Huang,
Alatancang Chen
Publication year - 2020
Publication title -
filomat
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.449
H-Index - 34
eISSN - 2406-0933
pISSN - 0354-5180
DOI - 10.2298/fil2004283l
Subject(s) - mathematics , numerical range , hilbert space , quadratic equation , operator (biology) , operator matrix , range (aeronautics) , inclusion (mineral) , mathematical analysis , pure mathematics , geometry , gender studies , biochemistry , chemistry , materials science , repressor , sociology , transcription factor , composite material , gene
This paper deals with the spectral inclusion properties of 2 x 2 operator matrices with unbounded entries in Hilbert space. The conditions for spectral inclusion by the quadratic numerical range are described. In addition, some examples are given to illustrate the main results.