proposition: Lemma BQopp_positive2 x: inc x BQp -> inc (BQopp x) BQm.
proof: Proof. move => /Zo_P [xq xp]; apply/Zo_i; first by apply: QSo. by rewrite /BQopp; aw;apply/BZopp_positive2. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)