Commuting graphs of Okubo algebras
Abstract
Commuting graphs of Okubo algebras are considered, and the problem of their connectivity is studied. The commuting graph of a pseudo-octonion algebra P8(π½) over a field π½, char π½ β 3, that contains a primitive cubic root of unity is shown to be isomorphic to the commuting graph of the matrix algebra M3(π½). As a consequence, if the field π½ is algebraically closed, then the diameter of the commuting graph for the unique Okubo algebra over π½ equals $4$. It is shown that the commuting graph of the real division Okubo algebra is connected, and its diameter also equals $4$. The proof of this result relies on the fact that, given any two idempotents in an arbitrary Okubo algebra, the intersection of their centralizers is always nonzero.
Versions
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BibTeX
@misc{zhilina2026commuting,
title = {{Commuting graphs of Okubo algebras}},
author = {Svetlana Zhilina and Danil Pavlinov},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28006},
eprint = {2608.28006},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28006},
}
RIS
TY - UNPB
TI - Commuting graphs of Okubo algebras
AU - Svetlana Zhilina
AU - Danil Pavlinov
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28006
UR - https://arxiv.org/abs/2608.28006
AB - Commuting graphs of Okubo algebras are considered, and the problem of their connectivity is studied. The commuting graph of a pseudo-octonion algebra P_8(π½) over a field π½, char π½ β 3, that contains a primitive cubic root of unity is shown to be isomorphic to the commuting graph of the matrix algebra M_3(π½). As a consequence, if the field π½ is algebraically closed, then the diameter of the commuting graph for the unique Okubo algebra over π½ equals $4$. It is shown that the commuting graph of the real division Okubo algebra is connected, and its diameter also equals $4$. The proof of this result relies on the fact that, given any two idempotents in an arbitrary Okubo algebra, the intersection of their centralizers is always nonzero.
ER -