摘要
We study a family of means introduced by H. Hasegawa and D. Petz (1996) . Properties with respect to the parameter, such as monotonicity and logarithmic concavity, further, monotonicity and concavity in the mean variables are shown. Besides, the comparison between the Hasegawa-Petz mean and the geometric mean is completely solved. The connection to earlier results on operator monotonicity and some applications are also discussed.