proposition: Lemma widen_bseq_trans m n p (lemn : m <= n) (lenp : n <= p) (bs : m.-bseq T) : widen_bseq (leq_trans lemn lenp) bs = widen_bseq lenp (widen_bseq lemn bs).
proof: Proof. exact/val_inj. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype path)