English

Berezin number and Berezin norm inequalities for operator matrices

Functional Analysis 2024-08-14 v1

Abstract

We establish new upper bounds for Berezin number and Berezin norm of operator matrices, which are refinements of the existing bounds. Among other bounds, we prove that if A=[Aij]A=[A_{ij}] is an n×nn\times n operator matrix with AijB(H)A_{ij}\in\mathbb{B}(\mathcal{H}) for i,j=1,2ni,j=1,2\dots n, then Aber[Aijber]\|A\|_{ber} \leq \left\|\left[\|A_{ij}\|_{ber}\right]\right\| and ber(A)w([aij]),\textbf{ber}(A) \leq w([a_{ij}]), where aii=ber(Aii),a_{ii}=\textbf{ber}(A_{ii}), aij=Aij+Ajiber12Aji+Aijber12a_{ij}=\big\||A_{ij}|+|A^*_{ji}|\big\|^{\frac{1}{2}}_{ber} \big\||A_{ji}|+|A^*_{ij}|\big\|^{\frac{1}{2}}_{ber} if i<ji<j and aij=0a_{ij}=0 if i>ji>j. Further, we give some examples for the Berezin number and Berezin norm estimation of operator matrices on the Hardy-Hilbert space.

Keywords

Cite

@article{arxiv.2306.02942,
  title  = {Berezin number and Berezin norm inequalities for operator matrices},
  author = {Pintu Bhunia and Anirban Sen and Somdatta Barik and Kallol Paul},
  journal= {arXiv preprint arXiv:2306.02942},
  year   = {2024}
}