Automorphism groups of quandles arising from groups
arXiv:1608.05178 · doi:10.1007/s00605-016-0994-x
Abstract
Let be a group and $φ\in \Aut(G)$. Then the set equipped with the binary operation gives a quandle structure on , denoted by $\Alex(G, φ)$ and called the generalised Alexander quandle. When is additive abelian and $φ= -\id_G$, then $\Alex(G, φ)$ is the well-known Takasaki quandle. In this paper, we determine the group of automorphisms and inner automorphisms of Takasaki quandles of abelian groups with no 2-torsion, and Alexander quandles of finite abelian groups with respect to fixed-point free automorphisms. As an application, we prove that if and is multiplication by a non-trivial unit of , then $\Aut\big(\Alex(G, φ)\big)$ acts doubly transitively on $\Alex(G, φ)$. This generalises a recent result of \cite{Ferman} for quandles of prime order.
11 pp, minor typo corrected