(* Leo: OUT-OF-SCOPE *)

Example trans_eq_exercise : forall (n m o p : nat),
     m = (minustwo o) ->
     (n + p) = m ->
     (n + p) = (minustwo o).

(* Specifications: *)
Theorem S_injective : forall (n m : nat), S n = S m -> n = m.
Theorem beq_nat_0_l : forall n, 0 = n -> n = 0.
Theorem inversion_ex4 : forall (n : nat), S n = O -> 2 + 2 = 5.
Theorem f_equal : forall (A B : Type) (f: A -> B) (x y: A), x = y -> f x = f y.
Theorem plus_n_n_injective : forall n m, n + n = m + m -> n = m.
Theorem double_injective : forall n m, double n = double m -> n = m.
Theorem beq_id_true : forall (x y : id), x = y -> x = y.
Theorem nth_error_after_last: forall (X : Type) (l : list X) (n : nat), length l = n -> nth_error l n = None.