Unitary similarity for dual complex matrices and dual quaternion matrices
Abstract
We study unitary similarity of dual complex matrices and dual quaternion matrices. First, we characterize unitary similarity in terms of the existence of a skew-Hermitian solution to a Sylvester-type matrix equation. For 2×2 dual complex matrices, we obtain a complete three-trace criterion when the standard part is nonnormal and analyze the limitations of trace-word criteria when the standard part is normal. We then prove, for every n≥1, that two n× n dual quaternion matrices are unitarily similar if and only if their dual complex adjoint matrices are unitarily similar, and we extend this result to finite families. As a scalar consequence, we derive a finite Trace-word criterion when the standard part is nonreal and exhibit its failure when the standard part is real.
Related
- Diagonalization of skew-Hermitian dual quaternion matrices and ϕ-Hermitian dual quaternion matrices
- Efficient Low-Rank Approximation of Quaternion Matrices via Adaptive Cross Approximation
- Dual Quaternion Discrete Linear Canonical Transforms: FFT-Based Fast Algorithms and Joint Rotation--Translation Pose Denoising
- Averages of traces and ratios of characteristic polynomials of random unitary matrices
- On Trace Averages and Sharp Asymptotics for Powers of Haar-Unitary Matrices
BibTeX
@misc{yao2026unitary,
title = {{Unitary similarity for dual complex matrices and dual quaternion matrices}},
author = {Cailing Yao and Bingzhe Hou and Xiaoqi Feng},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30060},
eprint = {2610.30060},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30060},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Unitary similarity for dual complex matrices and dual quaternion matrices
AU - Cailing Yao
AU - Bingzhe Hou
AU - Xiaoqi Feng
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.30060
UR - https://arxiv.org/abs/2610.30060
AB - We study unitary similarity of dual complex matrices and dual quaternion matrices. First, we characterize unitary similarity in terms of the existence of a skew-Hermitian solution to a Sylvester-type matrix equation. For 2×2 dual complex matrices, we obtain a complete three-trace criterion when the standard part is nonnormal and analyze the limitations of trace-word criteria when the standard part is normal. We then prove, for every n≥1, that two n× n dual quaternion matrices are unitarily similar if and only if their dual complex adjoint matrices are unitarily similar, and we extend this result to finite families. As a scalar consequence, we derive a finite Trace-word criterion when the standard part is nonreal and exhibit its failure when the standard part is real.
ER -