proposition: Lemma liftU k x : fglift << k *g x >> = k *: f x.
proof: Proof. by rewrite fglift_Freeg prelift_seq1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)