On various types of nilpotency of the structure monoid and group of a set-theoretic solution of the Yang--Baxter equation

F. Cedó, E. Jespers, Ł. Kubat +2

Given a finite bijective non-degenerate set-theoretic solution $(X,r)$ of the Yang--Baxter equation we characterize when its structure monoid $M(X,r)$ is Malcev nilpotent. Applying…