proposition: Lemma size_widen_bseq m n (lemn : m <= n) (bs : m.-bseq T) : size (widen_bseq lemn bs) = size bs.
proof: Proof. by []. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype path)