Hypermaps Over Non-Abelian Simple Groups and Strongly Symmetric Generating Sets

  • Andrea Lucchini
  • Pablo Spiga


A generating pair $x, y$ for a group $G$ is said to be symmetric if there exists an automorphism $\varphi_{x,y}$ of $G$ inverting both $x$ and $y$, that is, $x^{\varphi_{x,y}}=x^{-1}$ and $y^{\varphi_{x,y}}=y^{-1}$. Similarly, a group $G$ is said to be strongly symmetric if $G$ can be generated with two elements and if all generating pairs of $G$ are symmetric.

In this paper we classify the finite strongly symmetric non-abelian simple groups. Combinatorially, these are the finite non-abelian simple groups $G$ such that every orientably regular hypermap with monodromy group $G$ is reflexible.

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