proposition: Lemma lez0_nat n : n <= 0 :> int = (n == 0 :> nat).
proof: Proof. by elim: n. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)