proposition: Lemma prelift_seq1 k x : prelift [:: (k, x)] = k *: f x.
proof: Proof. exact: big_seq1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)