English

Concavity of certain matrix trace and norm functions. II

Functional Analysis 2015-09-23 v3

Abstract

We refine Epstein's method to prove joint concavity/convexity of matrix trace functions of Lieb type Trf(Φ(Ap)1/2Ψ(Bq)Φ(Ap)1/2)\mathrm{Tr}\,f(\Phi(A^p)^{1/2}\Psi(B^q)\Phi(A^p)^{1/2}) and symmetric (anti-) norm functions of the form f(Φ(Ap)σΨ(Bq))\|f(\Phi(A^p)\,\sigma\,\Psi(B^q))\|, where Φ\Phi and Ψ\Psi are positive linear maps, σ\sigma is an operator mean, and f(xγ)f(x^\gamma) with a certain power γ\gamma is an operator monotone function on (0,)(0,\infty). Moreover, the variational method of Carlen, Frank and Lieb is extended to general non-decreasing convex/concave functions on (0,)(0,\infty) so that we prove joint concavity/convexity of more trace functions of Lieb type.

Keywords

Cite

@article{arxiv.1507.00853,
  title  = {Concavity of certain matrix trace and norm functions. II},
  author = {Fumio Hiai},
  journal= {arXiv preprint arXiv:1507.00853},
  year   = {2015}
}

Comments

28 pages, a number of minor changes, Lemma A.3 added

R2 v1 2026-06-22T10:05:07.675Z