proposition: Lemma rsymrel_refl IS : reflexive (rsymrel IS).
proof: Proof. by rewrite /rsymrel=> k /=; rewrite eqxx. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(fingroup perm morphism presentation) mathcomp(ssralg poly ssrint) permcomp tools permuted combclass congr