proposition: Lemma RtointN x : x \is a Rint -> Rtoint (- x) = - Rtoint x.
proof: Proof. move=> Ir; apply/eqP. by rewrite -(@eqr_int R) RtointK // ?rpredN // mulrNz RtointK. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra) mathcomp(mathcomp_extra boolp classical_sets set_interval) Setoid