proposition: Lemma BQsum_Mlelt0 a b c : a <=q c -> b <q \0q -> (a +q b) <q c.
proof: Proof. by move => pa pb; move: (BQsum_Mlelt pa pb); rewrite (BQsum_0r (proj32 pa)). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)