R-equivalence classes of $\mathrm{Rot} \mathbb{E}^{2}$-colorings of torus knots
Mai Sato
TL;DR
This work addresses the problem of classifying R-equivalence classes of non-trivial $Rot\mathbb{E}^{2}$-colorings on torus-knot diagrams $D(p,q)$. It builds on Inoue's trochoid parametrization, connecting colorings with $(|p|,k;|q|,l)$-trochoids and analyzing their behavior under Reidemeister moves via two geometric deformations: shifts and switches. The main result shows that, when the parity condition $p'q'$ is even, R-equivalence is generated by shifts and even counts of switches, effectively reducing classification to a combinatorial action; the paper also establishes two necessary conditions for R-equivalence using quandle 2-cocycles and weights. An appendix relates cyclotomic unit theory to the algebraic structure underlying the colorings, highlighting deeper number-theoretic aspects of the problem.
Abstract
We introduce a new equivalence relation, named R-equivalence relation, on the set of colorings of an oriented knot diagram by a quandle. We determine the R-equivalence classes of colorings of a diagram of a torus knot by a quandle, called $\mathrm{Rot} \mathbb{E}^{2}$, under a certain condition.
