Let x0 of type ι be given.
Apply nat_ind with
λ x1 . ∀ x2 . (∀ x3 . x3 ∈ x1 ⟶ ap x2 x3 ∈ field0 x0) ⟶ ∀ x3 . x3 ∈ field0 x0 ⟶ CRing_with_id_eval_poly x0 x1 x2 x3 ∈ field0 x0 leaving 2 subgoals.
Let x1 of type ι be given.
Assume H1:
∀ x2 . x2 ∈ 0 ⟶ ap x1 x2 ∈ field0 x0.
Let x2 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Let x3 of type ι be given.
Apply nat_primrec_S with
field3 x0,
λ x4 x5 . field1b x0 (field2b x0 (ap x2 x4) (CRing_with_id_omega_exp x0 x3 x4)) x5,
x1,
λ x4 x5 . x5 ∈ field0 x0 leaving 2 subgoals.
The subproof is completed by applying H1.
Apply CRing_with_id_plus_clos with
x0,
field2b x0 (ap x2 x1) (CRing_with_id_omega_exp x0 x3 x1),
nat_primrec (field3 x0) (λ x4 x5 . field1b x0 (field2b x0 (ap x2 x4) (CRing_with_id_omega_exp x0 x3 x4)) x5) x1 leaving 3 subgoals.
The subproof is completed by applying H0.
Apply CRing_with_id_mult_clos with
x0,
ap x2 x1,
CRing_with_id_omega_exp x0 x3 x1 leaving 3 subgoals.
The subproof is completed by applying H0.
Apply H3 with
x1.
The subproof is completed by applying ordsuccI2 with x1.
Apply CRing_with_id_omega_exp_clos with
x0,
x3,
x1 leaving 3 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H4.
Apply nat_p_omega with
x1.
The subproof is completed by applying H1.
Claim L5:
∀ x4 . x4 ∈ x1 ⟶ ap x2 x4 ∈ field0 x0
Let x4 of type ι be given.
Assume H5: x4 ∈ x1.
Apply H3 with
x4.
Apply ordsuccI1 with
x1,
x4.
The subproof is completed by applying H5.
Apply H2 with
x2,
x3 leaving 2 subgoals.
The subproof is completed by applying L5.
The subproof is completed by applying H4.
Let x1 of type ι be given.
Assume H2:
x1 ∈ omega.
Let x2 of type ι be given.
Apply L1 with
x1,
x2 leaving 2 subgoals.
Apply omega_nat_p with
x1.
The subproof is completed by applying H2.
Let x3 of type ι be given.
Assume H4: x3 ∈ x1.
Apply ap_Pi with
x1,
λ x4 . field0 x0,
x2,
x3 leaving 2 subgoals.
The subproof is completed by applying H3.
The subproof is completed by applying H4.