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.
AMS Subject Classification
(1991): 47A30, 47A05, 47B15
closed range operator,
partial isometry operator,
Received April 8, 2017, and in final form November 25, 2017. (Registered under 23/2017.)