English

On an operator Kantorovich inequality for positive linear maps

Functional Analysis 2012-12-27 v1

Abstract

We improve the operator Kantorovich inequality as follows: Let AA be a positive operator on a Hilbert space with 0<mAM0<m\le A \le M. Then for every unital positive linear map Φ\Phi, Φ(A1)2((M+m)24Mm)2Φ(A)2.\Phi(A^{-1})^2\le (\frac{(M+m)^2}{4Mm})^2\Phi(A)^{-2}. As a consequence, Φ(A1)Φ(A)+Φ(A)Φ(A1)(M+m)22Mm.\Phi(A^{-1})\Phi(A)+\Phi(A)\Phi(A^{-1}) \le \frac{(M+m)^2}{2Mm}.

Keywords

Cite

@article{arxiv.1212.5690,
  title  = {On an operator Kantorovich inequality for positive linear maps},
  author = {Minghua Lin},
  journal= {arXiv preprint arXiv:1212.5690},
  year   = {2012}
}
R2 v1 2026-06-21T22:59:20.560Z