proposition: Lemma afix_ract B : 'Fix_(to \ sAD)(B) = 'Fix_to(B).
proof: Proof. by []. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(fintype bigop finset fingroup morphism perm) mathcomp(automorphism quotient)