proposition: Lemma comparablerE x y : (x >=< y)%R = (x - y \is Num.real).
proof: Proof. by rewrite -comparabler0 subr_comparable0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)