proposition: Lemma BRsum_Mlege0 a c d: a <=r c -> \0r <=r d -> a <=r (c +r d).
proof: Proof. by move => pa pb; move: (BRsum_Mlele pa pb); rewrite (BRsum_0r (proj31 pa)). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)