proposition: Lemma le_bound_trans : transitive le_bound.
proof: Proof. by case=> [[]?|[]] [[]?|[]] [[]?|[]] lexy leyz //; apply: (lteif_imply _ (lteif_trans lexy leyz)). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(div fintype bigop order ssralg finset fingroup) mathcomp(ssrnum)