English

Estimates on singular values of functions of perturbed operators

Functional Analysis 2016-05-18 v2

Abstract

This is a conitunation of [1] and [2]. We prove that if function ff belongs to the class Λω=def{f:ωf(δ)constω(δ)}\Lambda_{\omega} \overset{\text{def}}{=} \{f: \omega_{f}(\delta)\leq \text{const} \omega(\delta)\} for an arbitrary modulus of continuity ω\omega, then sj(f(A)f(B))cω((1+j)1pABSpl)fΛωs_j(f(A)-f(B))\leq c\cdot \omega_{\ast}\big((1+j)^{-\frac{1}{p}}\Vert A-B \Vert_{S_{p}^l}\big) \cdot \Vert f \Vert_{\Lambda_{\omega}} for arbitrary self-adjoint operators AA, BB and all 1jl1\leq j\leq l, where ω(x)=defxxω(t)t2dt(x>0)\omega_{\ast}(x) \overset{\text{def}}{=} x \int_{x}^{\infty}\frac{\omega(t)}{t^2}dt ( x>0) . The result is then generalized for contractions, maximal dissipative operators, normal operators and nn-tuples of commuting self-adjoint operators.

Keywords

Cite

@article{arxiv.1605.03931,
  title  = {Estimates on singular values of functions of perturbed operators},
  author = {Qinbo Liu},
  journal= {arXiv preprint arXiv:1605.03931},
  year   = {2016}
}