Bouraya C, Ameur S.
On the characterizations of some distinguished subclasses of Hilbert space operators. Acta Scientiarum Mathematicarum. 2018;84 (34) :611-627.
Abstract
In this note, we present several characterizations for some distinguished classes of bounded Hilbert space operators (self-adjoint operators, normal operators, unitary operators, and isometry operators) in terms of operator inequalities.