Correction to "Quaternionic Davis–Wielandt shell in a right quaternionic Hilbert space'', Ukrainian Mathematical Journal, vol. 75, No. 6, November, 2023 (Ukrainian original vol. 75, No. 6, June, 2023)

Authors

  • Aref Jeribi Department of Mathematics, Faculty of Sciences of Sfax, University of Sfax, Tunisia
  • Kamel Mahfoudhi University of Sousse, Higher Institute of Applied Sciences and Technology of Sousse, Tunisia

DOI:

https://doi.org/10.3842/umzh.v77i10.9201

Keywords:

Quaternion, quaternionic Hilbert space, Numerical range

Abstract

UDC 517.5

We correct a mistake made in the proof of Example 2.1. In fact $\langle T\phi,\phi\rangle_{\mathbb{H}}=0$ is not true in the case where $T=\begin{pmatrix}  \mathbf{q} & 0 \\0 & -\mathbf{q}\\\end{pmatrix}.$

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Published

30.09.2025

Issue

Vol. 77 No. 10 (2025)

Section

Research articles