English

On symmetricity of the norm derivatives orthogonality in operator spaces

Functional Analysis 2025-12-15 v1

Abstract

We investigate ρ\rho-orthogonality and its local symmetry in the space of bounded linear operators. A characterization of Hilbert space operators with symmetric numerical range is established in terms of ρ\rho-orthogonality. Further, we provide characterizations of ρ\rho-left and ρ\rho-right symmetric operators on finite-dimensional Hilbert spaces. In the two-dimensional real case, we show that the only nonzero ρ\rho-left (or ρ\rho-right) symmetric operators are scalar multiples of orthogonal matrices. However, in any finite-dimensional Hilbert space of dimension greater than two, an operator is ρ\rho-left (or ρ\rho-right) symmetric if and only if it is the zero operator. For infinite-dimensional spaces, we show that within a large class of operators, the zero operator remains the only example of ρ\rho-left and ρ\rho-right symmetric operators.

Keywords

Cite

@article{arxiv.2512.11208,
  title  = {On symmetricity of the norm derivatives orthogonality in operator spaces},
  author = {Souvik Ghosh and Kallol Paul and Debmalya Sain},
  journal= {arXiv preprint arXiv:2512.11208},
  year   = {2025}
}