proposition: Lemma atransR G : [transitive G, on G | 'R].
proof: Proof. by rewrite /atrans -{1}(mul1g G) -orbitR imset_f. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)