proposition: Fact meetUl : left_distributive (@meet n T) (@join n T).
proof: Proof. move=> t1 t2 t3; apply: eq_from_tnth => i. by rewrite !(tnth_meet, tnth_join) meetUl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)