Some inequalities for functions defined by power series concerning two operators in both the noncommutative and commutative case are given. Natural examples for fundamental functions that can be represented by power series are presented as well.
"Some Inequalities for Power Series of Two Operators in Hilbert Spaces." Tokyo J. Math. 36 (2) 483 - 498, December 2013. https://doi.org/10.3836/tjm/1391177983