English

Parallelism in Hilbert $K(\mathcal{H})$-modules

Functional Analysis 2018-12-04 v1

Abstract

Let (H,[,])(\mathcal{H}, [\cdot, \cdot ]) be a Hilbert space and K(H)K(\mathcal{H}) be the CC^*-algebra of compact operators on H\mathcal{H}. In this paper, we present some characterizations of the norm-parallelism for elements of a Hilbert K(H)K(\mathcal{H})-module E\mathcal{E} by employing the minimal projections on H\mathcal{H}. Let T,SL(E)T,S\in \mathcal{L(\mathcal{E})}. We show that TST \| S if and only if there exists a sequence of basic vectors {xn}ξn\{x_n\}^{\xi_n} in E\mathcal{E} such that limn[Txn,Sxnξn,ξn]=λTS\lim_n [\langle Tx_n, Sx_n \rangle \xi_n, \xi_n ] = \lambda\| T\| \| S\| for some λT\lambda \in \mathbb{T}. In addition, we give some equivalence assertions about the norm-parallelism of "compact" operators on a Hilbert CC^*-module.

Keywords

Cite

@article{arxiv.1812.00164,
  title  = {Parallelism in Hilbert $K(\mathcal{H})$-modules},
  author = {M. Mohammadi Gohari and M. Amyari},
  journal= {arXiv preprint arXiv:1812.00164},
  year   = {2018}
}
R2 v1 2026-06-23T06:27:47.529Z