English

Operator mean inequalities for sector matrices

Functional Analysis 2023-05-09 v1

Abstract

In this note, some inequalities involving operator means of sectorial matrices are proved which are generalizations and refinements of previous known results. Among them, let AA and BB be two accretive matrices with A,BSθA,B\in\mathcal{S}_{\theta}, 0<mIA,BMI0 < mI \leqslant A, B \leqslant MI for positive real numbers M,m,σ M, m, \, \sigma be an operator mean and σ\sigma^{*} be the adjoint mean of σ. \sigma. If σσ1,σ2σ\sigma^*\leqslant \sigma_1,\sigma_2\leqslant \sigma and Φ\Phi is a positive unital linear map, then Φp(Aσ1B)sec2pθαpΦp(Aσ2B),\Phi^{p}\Re(A \sigma_{1} B) \leqslant \sec^{2p}\theta\alpha^{p} \Phi^{p}\Re(A \sigma_{2} B), where α=max{K,412pK}, \alpha= \max \left \lbrace K, 4^{1-\frac{2}{p}}K \right \rbrace, and K=(M+m)24mM K= \frac{(M+m)^2}{4mM} is the Kantorovich constant.

Keywords

Cite

@article{arxiv.2305.04494,
  title  = {Operator mean inequalities for sector matrices},
  author = {M. Khosravi and A. Sheikhhosseini and S. Malekinejad},
  journal= {arXiv preprint arXiv:2305.04494},
  year   = {2023}
}
R2 v1 2026-06-28T10:28:23.144Z