proposition: Lemma signr_ge0 (b : bool) : (0 <= (-1) ^+ b :> R) = ~~ b.
proof: Proof. by rewrite le0r signr_eq0 signr_gt0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)