proposition: Lemma le_def' x y : (x <= y) = (x == y) || (x < y).
proof: Proof. by rewrite lt_def; case: eqVneq => //= ->; rewrite lerr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)