proposition: Lemma BQopp_compatZ x: BQopp (BQ_of_Z x) = BQ_of_Z (BZopp x).
proof: Proof. by rewrite /BQopp /BZ_of_Z /BQ_of_Z;aw. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype order) mathcomp(ssrnat ssrint ssralg ssrnum div)