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I'm looking for graph $G$, $V(G) >2$, such that$G \cong Cay(Aut(G), S) $, where $Cay$ is the Cayley graph (considered as undirected graph) and $S$ is minimal generator of $G$.

I've written a GAP code that looped through $\Gamma$ groups, and formed $G'=Cay(\Gamma)$ and $G''=Cay(Aut(G')) $. After it checked if $G' \cong G''$ is true. It happened to be false for the first 1000 groups, except when $\Gamma$ is the trivial group and when it is isomorphic to $C_2$.

Now, I am not even sure what generator set was used by GAP. Is it possible that for other generator set it would work? Maybe if it isn't minimal?

Thanks in advance!

  • See https://math.stackexchange.com/questions/1098115/when-is-the-automorphism-group-of-the-cayley-graph-of-g-just-g – Misha Lavrov Nov 05 '18 at 23:45
  • I'm guessing you mean $Aut(Cay(..$ not $Cay(Aut(...$. – verret Nov 05 '18 at 23:57
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    If you want a specific example, take $G$ to be the dihedral group of order $12$, let $a$ be a basic rotation (of order 6) and $b$ a reflection, then take $S={a,a^{-1},b,ba,ba^3}$. The automorphism group of this graph is $G$. (There are no examples of order less than $12$.) – verret Nov 06 '18 at 00:04

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