proposition: Lemma monotonous_in_contravariant : forall D E f, included D E -> monotonous_in E f -> monotonous_in D f.
proof: Proof. intros D E f inc [f_dec | f_inc] ; [left ; eapply decreasing_in_contravariant | right ; eapply increasing_in_contravariant] ; eassumption. Qed.
imports: Rbase Ranalysis Rinterval Rfunctions Rfunction_def Ranalysis_def Rfunction_facts MyRIneq MyR_dist Lra