proposition: Lemma lqt23 a b c : a <= b < c -> b < c.
proof: Proof. by case/andP. Qed.
imports: Coq(ssreflect ssrbool ssrfun Eqdep) mathcomp(ssrnat seq eqtype choice fintype) pcm(options axioms) Coq(Classes.Morphisms Program.Basics Program.Tactics) Coq(Relations)