proposition: Lemma or_sub (T : eqType) (xs ys :seq T) (F : T -> pS) : {subset xs <= ys} -> mprv ((\or_(i<-xs) F i) ---> (\or_(j<-ys) F j)).
proof: Proof. move => H. apply: bigOE => s /H. exact: bigOI. Qed.
imports: mathcomp(all_ssreflect) CompDecModal.libs(edone base fset induced_sym) Setoid Morphisms Relation_Definitions