proposition: Theorem Cayley_isom G : isom G (Cayley_repr G @* G) (Cayley_repr G).
proof: Proof. exact: faithful_isom (faithfulR G). Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)