Generalized Alexander quandles of finite groups and their characterizations

The goal of this paper is to characterize generalized Alexander quandles of finite groups in the language of the underlying groups. Firstly, we prove that if finite groups G are simple, then the quandle isomorphic classes of generalized Alexander quandles of G one-to-one correspond to the conjugacy classes of the automorphism groups of G. This correspondence can be also claimed for the case of symmetric groups. Secondly, we give a characterization of generalized Alexander quandles of finite groups G under some assumptions in terms of G. As corollaries of this characterization, we obtain several characterizations to some particular groups, e.g., abelian groups and dihedral groups. Finally, we perform a characterization of generalized Alexander quandles arising from groups with their order up to 15.