proposition: Fact lez_anti m : lez 0 m -> lez m 0 -> m = 0.
proof: Proof. by case: m; first case. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)