proposition: Lemma Rtointz (z : int): Rtoint z%:~R = z.
proof: Proof. by apply/eqP; rewrite -(@eqr_int R) RtointK ?rpred_int. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra) mathcomp(mathcomp_extra boolp classical_sets set_interval) Setoid