On derived-indecomposable solutions of the Yang--Baxter equation

Ilaria Colazzo, Maria Ferrara, Marco Trombetti

If $(X,r)$ is a finite non-degenerate set-theoretic solution of the Yang--Baxter equation, the additive group of the structure skew brace $G(X,r)$ is an $FC$-group, i.e. a group wh…