intros; intro.
simpl in |- *.
auto with algebra.
Qed.
Hint Resolve Seqtl_modify_seq.

(* Specifications: *)
Lemma modify_seq_defprop :
forall (A : Setoid) (n : Nat) (v : seq n A) (i : fin n) (a : A),
modify_seq v i a i =' a in _.