proposition: Fact lt0N x : (- x < 0) = (0 < x).
proof: Proof. by rewrite -sub_gt0 add0r opprK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)