proposition: Lemma rNorm (kS : kSystem) (s t : kS) : mprv (s ---> t) -> mprv (AX s ---> AX t).
proof: Proof. move => H. rule axN. exact: rNec. Qed.
imports: mathcomp(all_ssreflect) CompDecModal.libs(edone base fset induced_sym) Setoid Morphisms Relation_Definitions