Ismail Nikoufar - Department of Mathematics, Payame Noor University, Tehran, Iran

In this paper, we find upper and lower bounds of some operator entropies. Wealso refine and improve the lower and upper bound of these operator entropies. Asa consequence of our result, we improve the bounds of the relative operator entropyannounced by Fujii and Kamei

perspective function, relative operator entropy, Tsallis relative operatorentropy, generalized relative operator, operator geometric mean