proposition: Lemma reduced_uniq D : reduced D -> uniq [seq zx.2 | zx <- D].
proof: Proof. by case/andP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)