(* Replacing BVxor *)
Definition BLxor (xs : Blist) (ys : Blist) :=
  map (fun p => xorb (fst p) (snd p)) (combine xs ys).

Theorem xor_eq : forall (n : nat) (v1 v2 : Bvector.Bvector n), BLxor (Vector.to_list v1) (Vector.to_list v2) = Vector.to_list (Bvector.BVxor n v1 v2).