The symmetry group of Turk's head knots
Abstract
For p, q >= 3 with gcd(p,q) = 1 we show that the symmetry group of the Turk's head knot Th(p,q), the closure of the braid (sigma_1 sigma_2^{-1} sigma_3 sigma_4^{-1} ... sigma_{p-1}^{+-1})^q, is the dihedral group of order 4q. This proves Conjecture R of Di Prisa and Şavk for q >= 3; the case p = 3 is due to Sakuma and Weeks. The argument is diagrammatic: by the flyping theorem of Menasco and Thistlethwaite, the symmetries of a knot with a prime, reduced alternating diagram without non-trivial flypes are the symmetries of the diagram (we write out a proof for the diagrams at hand), and we show that the standard diagram of Th(p,q) has no non-trivial flypes and exactly 4q symmetries. The chirality of Th(p,q) for even p, which also follows from a theorem of Murasugi, is visible in the group. We compare the argument with the geometric one of Sakuma and Weeks for p = 3.
Related
- Amphichiral Knots: Odd Braid Index and Symmetry Classification in the Three-Braid Case
- The Weighted Dual Minkowski Problem Under Group Symmetry
- The Symmetry of Differential Neural Tangent Kernel under the Orthogonal Group
- New inhomogeneous Bismut Hermitian-Einstein threefolds with large symmetry group
- A Clustered Equivalent-Source Method with Local Response Compression and Group-Symmetry Reduction for Antenna-Array Analysis
BibTeX
@misc{stanggassinger2026symmetry,
title = {{The symmetry group of Turk's head knots}},
author = {Werner Alois Stanggassinger},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16600},
eprint = {2610.16600},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16600},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The symmetry group of Turk's head knots
AU - Werner Alois Stanggassinger
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.16600
UR - https://arxiv.org/abs/2610.16600
AB - For p, q >= 3 with gcd(p,q) = 1 we show that the symmetry group of the Turk's head knot Th(p,q), the closure of the braid (sigma_1 sigma_2^{-1} sigma_3 sigma_4^{-1} ... sigma_{p-1}^{+-1})^q, is the dihedral group of order 4q. This proves Conjecture R of Di Prisa and Şavk for q >= 3; the case p = 3 is due to Sakuma and Weeks. The argument is diagrammatic: by the flyping theorem of Menasco and Thistlethwaite, the symmetries of a knot with a prime, reduced alternating diagram without non-trivial flypes are the symmetries of the diagram (we write out a proof for the diagrams at hand), and we show that the standard diagram of Th(p,q) has no non-trivial flypes and exactly 4q symmetries. The chirality of Th(p,q) for even p, which also follows from a theorem of Murasugi, is visible in the group. We compare the argument with the geometric one of Sakuma and Weeks for p = 3.
ER -