proposition: Lemma le0_funenegE f : (forall x, D x -> f x <= 0) -> {in D, f^\- =1 \- f}.
proof: Proof. by move=> f0 x; rewrite inE => Dx; apply/max_idPl; rewrite leeNr oppe0 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