proposition: Lemma BQopp_positive1 x: inc x BQps -> inc (BQopp x) BQms.
proof: Proof. move => /Zo_P [xq xp]; apply/Zo_i; first by apply:QSo. by rewrite /BQopp; aw;apply/BZopp_positive1. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)