proposition: Lemma ler_restrict D f g : (forall x, D x -> f x <= g x) -> forall x, (f \_ D) x <= (g \_ D) x.
proof: Proof. by move=> f0 x; rewrite /patch; case: ifP => // /set_mem/f0->. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum ssrint interval finmap) mathcomp(mathcomp_extra boolp classical_sets fsbigop) mathcomp(functions cardinality set_interval) signed reals ereal topology normedtype sequences