proposition: Lemma fgneg_le0 D : 0 <=g fgneg D.
proof: Proof. by rewrite -fgposN fgpos_le0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)