proposition: Lemma decnP : (forall i, f i > f i.+1) -> {mono f : i j /~ i <= j}.
proof: Proof. by move=> f_dec; apply/le_nmono/nhomo_ltn_lt. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)