Sun, Chuankun On essential norm of elementary operator \(\Gamma: T\to ATB\). (Chinese. English summary) Zbl 0696.47008 Northeast. Math. J. 4, No. 4, 458-462 (1988). Summary: This paper describes the relation between essential norm of the operator \(\Gamma: T\to ATB\) and those of operators A and B. It is shown that \[ \| \Gamma \|_ e=\max \{\| A\|_ e\| B\|,\| A\| \| B\|_ e\}. \] MSC: 47A30 Norms (inequalities, more than one norm, etc.) of linear operators 47B47 Commutators, derivations, elementary operators, etc. Keywords:elementary operator; essential norm PDFBibTeX XMLCite \textit{C. Sun}, Northeast. Math. J. 4, No. 4, 458--462 (1988; Zbl 0696.47008)