proposition: Corollary af_cofmap (X Y:Type) (f:Y->X) (R:X->X->Prop): almost_full R -> almost_full (fun x y => R (f x) (f y)).
proof: Proof. intros (p,Rsec). exists (cofmap f p). apply cofmap_secures; auto. Defined.
imports: Coq(Lia) AlmostFull.Default(AlmostFull)