proposition: Lemma gact1 : {in D, forall a, to 1 a = 1}.
proof: Proof. by move=> a Da; rewrite /= -actmE ?morph1. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)