proposition: Lemma signr_lt0 (b : bool) : ((-1) ^+ b < 0 :> R) = b.
proof: Proof. by case: b; rewrite // ?(ltrN10, ltr10). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)