We investigate the metric geometry of gyrogroups, a class of group-like structures whose binary operation is generally nonassociative. In particular, we extend the notion of the word metric from finitely generated groups to gyrogroups. This extension enables any gyrogroup to be viewed as a metric space, providing a suitable framework for proving a Mazur–Ulam-type theorem and for analyzing its algebraic and combinatorial structure via the associated right Cayley graph in a manner analogous to the classical setting of groups.
Citation: Teerapong Suksumran. Generalized word metrics and a Mazur–Ulam-type theorem for gyrogroups[J]. Electronic Research Archive, 2026, 34(6): 4037-4050. doi: 10.3934/era.2026181
We investigate the metric geometry of gyrogroups, a class of group-like structures whose binary operation is generally nonassociative. In particular, we extend the notion of the word metric from finitely generated groups to gyrogroups. This extension enables any gyrogroup to be viewed as a metric space, providing a suitable framework for proving a Mazur–Ulam-type theorem and for analyzing its algebraic and combinatorial structure via the associated right Cayley graph in a manner analogous to the classical setting of groups.
| [1] | C. Löh, Geometric Group Theory: An Introduction, Springer, Cham, 2017. |
| [2] |
P. Patel, On the residual finiteness growths of particular hyperbolic manifold groups, Geom. Dedicata, 185 (2016), 87–103. https://doi.org/10.1007/s10711-016-0169-x doi: 10.1007/s10711-016-0169-x
|
| [3] | M. Bridson, A. Haefliger, Metric Spaces of Non-positive Curvature, Springer, Berlin, 1999. |
| [4] | W. Lück, Survey on geometric group theory, Münster J. Math., 1 (2008), 73–108, 2008. |
| [5] |
S. Kim, J. Lawson, Unit balls, Lorentz boosts, and hyperbolic geometry, Results Math., 63 (2013), 1225–1242. https://doi.org/10.1007/s00025-012-0265-7 doi: 10.1007/s00025-012-0265-7
|
| [6] | A. Ungar, Beyond the Einstein Addition Law and its Gyroscopic Thomas Precession: The Theory of Gyrogroups and Gyrovector Spaces, Springer, 2001. https://doi.org/10.1007/0-306-47134-5_11 |
| [7] |
A. Ungar, Einstein's velocity addition law and its hyperbolic geometry, Comput. Math. Appl., 53 (2007), 1228–1250. https://doi.org/10.1016/j.camwa.2006.05.028 doi: 10.1016/j.camwa.2006.05.028
|
| [8] | A. Ungar, Analytic Hyperbolic Geometry and Albert Einstein's Special Theory of Relativity, World Scientific, Hackensack, NJ, 2008. https://doi.org/10.1142/12478 |
| [9] |
J. Wattanapan, W. Atiponrat, T. Suksumran, Extension of the Švarc–Milnor lemma to gyrogroups, Rev. R. Acad. Cienc. Exactas Fís. Nat. Ser. A Mat., 115 (2021), 122. https://doi.org/10.1007/s13398-021-01062-y doi: 10.1007/s13398-021-01062-y
|
| [10] | T. Suksumran, Essays in Mathematics and its Applications: In Honor of Vladimir Arnold, Springer, Switzerland, 2016. https://doi.org/10.1007/978-3-319-31338-2 |
| [11] | T. Suksumran, A simple bound on the $\ell$-rank of finite gyrogroups, Eur. J. Pure Appl. Math., 19 (2026), 7399. |
| [12] | L. Bussaban, A. Kawekhao, S. Suantai, Cayley graphs of gyrogroups, Quasigroups Relat. Syst., 27 (2019), 25–32. |
| [13] | C. Godsil, G. Royle, Algebraic Graph Theory, Springer, New York, 2001. |
| [14] |
T. Abe, K. Watanabe, Finitely generated gyrovector subspaces and orthogonal gyrodecomposition in the Möbius gyrovector space, J. Math. Anal. Appl., 449 (2017), 77–90. https://doi.org/10.1016/j.jmaa.2016.11.039 doi: 10.1016/j.jmaa.2016.11.039
|
| [15] | T. Abe, O. Hatori, Generalized gyrovector spaces and a Mazur–Ulam theorem, Publ. Math. Debrecen, 87 (2015), 393–413. |
| [16] | T. Abe, Gyrometric preserving maps on Einstein gyrogroups, Möbius gyrogroups and proper velocity gyrogroups, Nonlinear Funct. Anal. Appl., 19 (2014), 1–17. |
| [17] | T. Suksumran, Mathematical Analysis and Applications, Springer, Cham, 2019. https://doi.org/10.1007/978-3-030-31339-5 |
| [18] |
T. Suksumran, K. Wiboonton, Isomorphism theorems for gyrogroups and L-subgyrogroups, J. Geom. Symmetry Phys., 37 (2015), 67–83. https://doi.org/10.7546/jgsp-37-2015-67-83 doi: 10.7546/jgsp-37-2015-67-83
|
| [19] |
R. Maungchang, P. Khachorncharoenkul, K. Prathom, T. Suksumran, On transitivity and connectedness of Cayley graphs of gyrogroups, Heliyon, 7 (2021), e07049. https://doi.org/10.1016/j.heliyon.2021.e07049 doi: 10.1016/j.heliyon.2021.e07049
|
| [20] |
R. van Dam, M. Jazaeri, On bipartite distance-regular Cayley graphs with small diameter, Electron. J. Combin., 29 (2022). https://doi.org/10.37236/10757 doi: 10.37236/10757
|