proposition: Lemma lt_bound_def b1 b2 : lt_bound b1 b2 = (b2 != b1) && le_bound b1 b2.
proof: Proof. by case: b1 b2 => [[]?|[]][[]?|[]] //=; rewrite lt_def. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(div fintype bigop order ssralg finset fingroup) mathcomp(ssrnum)