proposition: Lemma ByteString_mappend_assoc : forall l m n : ByteString, ByteString_append l (ByteString_append m n) = ByteString_append (ByteString_append l m) n.
proof: Proof. intros. rewrite (ByteString_into_BitString_eq m), (ByteString_into_BitString_eq n), (ByteString_into_BitString_eq l). erewrite !ByteString_mappend_BitString_into. rewrite app_assoc. reflexivity. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Bedrock.Word Coq.ZArith.ZArith Coq.NArith.NArith Coq.Arith.Arith Coq.Numbers.Natural.Peano.NPeano Coq.Logic.Eqdep_dec Fiat.Narcissus.Common.Specs