proposition: Lemma itv_bound_total : total (<=%O : rel (itv_bound T)).
proof: Proof. by move=> [[]?|[]][[]?|[]]; rewrite /<=%O //=; case: ltgtP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(div fintype bigop order ssralg finset fingroup) mathcomp(ssrnum)