English

New inequalities for operator concave functions involving positive linear maps

Functional Analysis 2018-03-01 v2

Abstract

The purpose of this paper is to present some general inequalities for operator concave functions which include some known inequalities as a particular case. Among other things, we prove that if AB(H)A\in \mathcal{B}\left( \mathcal{H} \right) is a positive operator such that mIAMImI\le A\le MI for some scalars 0<m<M0<m<M and Φ\Phi is a normalized positive linear map on B(H)\mathcal{B}\left( \mathcal{H} \right), then (M+m2Mm)r(1MmΦ(A)+MmΦ(A1)2)r1(Mm)r2Φ(A)r+(Mm)r2Φ(A1)r2Φ(A)rΦ(A1)r,\begin{aligned} {{\left( \frac{M+m}{2\sqrt{Mm}} \right)}^{r}}&\ge {{\left( \frac{\frac{1}{\sqrt{Mm}}\Phi \left( A \right)+\sqrt{Mm}\Phi \left( {{A}^{-1}} \right)}{2} \right)}^{r}} & \ge \frac{\frac{1}{{{\left( Mm \right)}^{\frac{r}{2}}}}\Phi {{\left( A \right)}^{r}}+{{\left( Mm \right)}^{\frac{r}{2}}}\Phi {{\left( {{A}^{-1}} \right)}^{r}}}{2} & \ge \Phi {{\left( A \right)}^{r}}\sharp\Phi {{\left( {{A}^{-1}} \right)}^{r}}, \end{aligned} where 0r10\le r\le 1, which nicely extend the operator Kantorovich inequality.

Keywords

Cite

@article{arxiv.1711.04957,
  title  = {New inequalities for operator concave functions involving positive linear maps},
  author = {S. Sheybani and M. E. Omidvar and H. R. Moradi},
  journal= {arXiv preprint arXiv:1711.04957},
  year   = {2018}
}

Comments

to appear in Math. Inequal. Appl

R2 v1 2026-06-22T22:45:09.567Z