Let n be given.
Assume Hn.
Let m be given.
Assume Hm.
We prove the intermediate claim Lnn: nat_p n.
An exact proof term for the current goal is omega_nat_p n Hn.
We prove the intermediate claim Lmn: nat_p m.
An exact proof term for the current goal is nat_p_trans n Lnn m Hm.
We prove the intermediate
claim Lm:
m ∈ ω.
An exact proof term for the current goal is nat_p_omega m Lmn.
rewrite the current goal using
SNoLev_eps_ m Lm (from left to right).
rewrite the current goal using
SNoLev_eps_ n Hn (from left to right).
We will
prove ordsucc m ∈ ordsucc n.
An exact proof term for the current goal is nat_ordsucc_in_ordsucc n Lnn m Hm.
rewrite the current goal using
SNoLev_eps_ m Lm (from left to right).
Let k be given.
We prove the intermediate claim Lk: ordinal k.
An exact proof term for the current goal is nat_p_ordinal k (nat_p_trans (ordsucc m) (nat_ordsucc m Lmn) k Hk).
Apply iffI to the current goal.
We will
prove 0 ∈ eps_ m.
We will
prove 0 ∈ {0} ∪ {(ordsucc j) '|j ∈ m}.
Apply binunionI1 to the current goal.
Apply SingI to the current goal.
We will
prove 0 ∈ eps_ n.
We will
prove 0 ∈ {0} ∪ {(ordsucc j) '|j ∈ n}.
Apply binunionI1 to the current goal.
Apply SingI to the current goal.
rewrite the current goal using
SNoLev_eps_ m Lm (from left to right).
Apply neq_ordsucc_0 m to the current goal.
We will prove ordsucc m = 0.
An
exact proof term for the current goal is
eps_ordinal_In_eq_0 n (ordsucc m) (ordinal_ordsucc m (nat_p_ordinal m Lmn)) H1.
∎