Instance CompSpecs : compspecs. make_compspecs prog. Defined.
Definition Vprog : varspecs.  mk_varspecs prog. Defined.
Definition Gprog: funspecs := nil.
Definition Delta1 : tycontext :=
ltac:(let x := constr:(func_tycontext f_sumarray Vprog Gprog nil)
in let y := eval hnf in x
in exact y).

Lemma exercise3:
forall n, 0 <= n <= Int.max_signed ->
Int.min_signed <= 0 <= n.