English

More on $\omega$-orthogonality and $\omega$-parallelism

Functional Analysis 2020-04-07 v2

Abstract

We investigate some aspects of various numerical radius orthogonalities and numerical radius parallelism for bounded linear operators on a Hilbert space H\mathscr{H}. Among several results, we show that if T,SB(H)T,S\in \mathbb{B}(\mathscr{H}) and Mω(T)=Mω(S)M^*_{\omega(T)}=M^*_{\omega(S)}, then TωBST\perp_{\omega B} S if and only if SωBTS\perp_{\omega B} T, where Mω(T)={{xn}:xn=1,limnTxn,xn=ω(T)}M^*_{\omega(T)}=\{\{x_n\}:\,\,\,\|x_n\|=1, \lim_n|\langle Tx_n, x_n\rangle|=\omega(T)\}, and ω(T)\omega(T) is the numerical radius of TT and ωB\perp_{\omega B} is the numerical radius Birkhoff orthogonality.

Keywords

Cite

@article{arxiv.2004.00453,
  title  = {More on $\omega$-orthogonality and $\omega$-parallelism},
  author = {Maryam Torabian and Maryam Amyari and Marzieh Moradian Khibary},
  journal= {arXiv preprint arXiv:2004.00453},
  year   = {2020}
}