The existence of unexpected automorphisms in direct product graphs

Xiaomeng Wang, Yan-Li Qin, Binzhou Xia

A pair of graphs $(\Gamma ,\Sigma )$ is called unstable if their direct product $\Gamma \times \Sigma$ admits automorphisms not from $\mathrm{Aut}(\Gamma )\times \mathrm{Aut}(\Sigma )$, and such automorphisms are said…