proposition: Lemma axAEl s t : mprv (s :/\: t ---> s).
proof: Proof. rewrite /And /Neg. rewrite <- (axDN s) at 2. rule axW. rule axC. exact: axContra. Qed.
imports: mathcomp(all_ssreflect) CompDecModal.libs(edone base fset induced_sym) Setoid Morphisms Relation_Definitions