A matrix formulation of Grüss inequality
The main result of this paper is Theorem 3.1: If \(A,B\) are bounded linear operations on a Hilbert space and their numerical ranges are contained in disks of radii \(R\) and \(S\) respectively, and \(T\) is a trace operator, then NEWLINE\[NEWLINE|Tr (TAB) -Tr (TA) Tr (TB) |\leq 4RSNEWLINE\]NEWLINE If \(A,B\) are normal, the \(4\) can be replaced by \(1\). This implies other well-known inequalities.
scientific article; zbMATH DE number 1661140