proposition: Lemma axAI s t : mprv (s ---> t ---> s :/\: t).
proof: Proof. rewrite /And /Neg. mp. mp. B. C. mp. C. done. Qed.
imports: mathcomp(all_ssreflect) CompDecModal.libs(edone base fset induced_sym) Setoid Morphisms Relation_Definitions