proposition: Lemma rRev1 (pS : pSystem) (s t : pS) : mprv (s ---> t) -> mprv ((\and_(<- [:: s]) ---> t)).
proof: Proof. rewrite big_cons => H. by rewrite -> axAEl. Qed.
imports: mathcomp(all_ssreflect) CompDecModal.libs(edone base fset induced_sym) Setoid Morphisms Relation_Definitions