Every group is the automorphism group of a set-theoretic solution of the Yang--Baxter equation
Abstract
We give an affirmative answer to the abstract group problem for the category YB of all set-theoretic solutions of the Yang--Baxter (YB) equation: every group is isomorphic to the automorphism group of a YB-solution, which can be chosen on a finite set if the group is finite. In the terminology of László Babai, this means that the category YB is universal and finitely universal, which is an analogue of Frucht's classical theorem for graphs. Furthermore, the YB-solutions can be chosen within three very small classes: the solutions of the Frobenius-Separability equation, the solutions of the Baaj--Long--Skandalis equation and the recently introduced bipartite solutions. The proof is based on new constructions which associate to any graph a YB-solution in each of these classes, with the same automorphism group as the graph. Explicit YB-solutions with automorphism groups Cn, Sn, Dn and Q8 are given.
Related
- A categorical approach to the set-theoretic Yang-Baxter equation
- A solution to the quantum Yang--Baxter equation associated with a universal two-valued algebraic group
- Centralizers of maps as automorphism groups of Yang--Baxter solutions
- NS-Leibniz bialgebras, the Yang--Baxter equation and relative Rota--Baxter operators
- Gaussian solutions to the Yang--Baxter equation and their twists
BibTeX
@misc{militaru2026every,
title = {{Every group is the automorphism group of a set-theoretic solution of the Yang--Baxter equation}},
author = {G. Militaru},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.39228},
eprint = {2610.39228},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.39228},
}
RIS
TY - UNPB
TI - Every group is the automorphism group of a set-theoretic solution of the Yang--Baxter equation
AU - G. Militaru
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.39228
UR - https://arxiv.org/abs/2610.39228
AB - We give an affirmative answer to the abstract group problem for the category YB of all set-theoretic solutions of the Yang--Baxter (YB) equation: every group is isomorphic to the automorphism group of a YB-solution, which can be chosen on a finite set if the group is finite. In the terminology of László Babai, this means that the category YB is universal and finitely universal, which is an analogue of Frucht's classical theorem for graphs. Furthermore, the YB-solutions can be chosen within three very small classes: the solutions of the Frobenius-Separability equation, the solutions of the Baaj--Long--Skandalis equation and the recently introduced bipartite solutions. The proof is based on new constructions which associate to any graph a YB-solution in each of these classes, with the same automorphism group as the graph. Explicit YB-solutions with automorphism groups C_n, S_n, D_n and Q_8 are given.
ER -