Young's inequality in trace-class operators
The classical Young inequality for complex numbers has been formulated for matrices and compact operators by \textit{T. Ando} [Oper. Theory, Adv. Appl. 75, 33--38 (1994; Zbl 0830.47010)] and \textit{J. Erlijman, D. R. Farenick} and \textit{R. Y. Zeng} [ibid. 130, 171--184 (2001; Zbl 1031.47013)], respectively. The characterization of the case of equality in the operator Young inequality for the Hilbert-Schmidt norm has been given by \textit{O. Hirzallah} and the reviewer [Linear Algebra Appl. 308, 77--84 (2000; Zbl 0957.15018)]. In this interesting paper, the authors characterize the case of equality in the operator Young inequality for the trace norm.
scientific article; zbMATH DE number 1944291