proposition: Lemma area_gt0 a b: (a < b) = (0 < area a b)%R.
proof: Proof. by rewrite /area subr_gt0. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype order bigop ssralg) mathcomp(div ssrnum ssrint rat prime path binomial) mathcomp(tuple finset) gaia(fibm)